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Journal of Clinical EEG & Neuroscience, April, 2011Abstracts of peer-reviewed presentations at the Australasian Cognitive Neurosciences Conference (20th meeting of the Australasian Society for Psychophysiology), November 26-29, 2010, Swinburne University of Technology, Melbourne, Australia.Abstracts of these presentations are listed in alphabetical order of the first author's surname. fMRI Based Localisation of V5 and Motion-Attention Related IPS Regions for Neuronavigated TMS Bonnie Alexander The heterogeneity of function attributed to the human intraparietal sulcus (IPS) has been emphasised frequently. The range of attention, spatial, visual and sensorimotor and other functions performed by this sulcus, and its role as an association area, creates complexity both in localising appropriate areas for TMS application, and in drawing conclusions from TMS results. Online fMRI-guided neuronavigation for TMS localisation offers more power for TMS experiments than offline MRI-guided localisation or other methods such as phosphene elicitation (Sack et al., 2009). In the current study, fMRI was employed with an attention-to-motion (ATM) task with the aim of localising area V5, and identifying the most appropriate attention-related regions of IPS for subsequent inhibitory TMS to gauge timing relevant for motion perception. Ten participants (four women, aged 18-35) performed the ATM task and a standard V5 localiser task in a 3T scanner. The ATM task featured four quadrants, presented non-foveally, of randomly moving dots. Participants responded to the presentation of a moving stimulus traversing one of these four quadrants in a pseudo-randomised order. Diffusion weighted imaging was also acquired. Results of a random effects analysis of the ATM task yielded functional maxima corresponding to area V5, as well as regions of interest in posterior IPS. Per participant analysis comparing left-hemifield with right-hemifield stimulus presentation yielded ipsilaterally and contralaterally responsive regions in IPS and elsewhere. Structural connectivity of possible TMS stimulation sites was preliminarily explored with white matter tractography seeded in these regions. Preliminary results are discussed. The Effects of Enriched Environment on the Development of Visual Recognition Memory and the Influence of Precocious Tactile Stimulation Anna Antinori and Nicoletta Berardi It has been previously shown how enriched environment (E.E) provided in the early stages of a rat’t life accelerates the development of the visual system. This project investigated if E.E can affect the development of higher functions such as Recognition Memory. Another issue was whether early tactile stimulation which mimics maternal care could also affect the development of visual recognition memory. Increased levels of maternal care, and particularly tactile stimulation through licking and grooming, may represent a key component in the early phases of E.E. To test the development of Recognition Memory the Objection Recognition test (O.R.T) was used in 5 different stages of the animals’ lives: post-natal day 18 (P18), P25, P30, P40, P60. For each stage memory of the animals was tested at 4 temporal interval 1h, 24h, 48h, 72h. using a total of 92 black hooded rats. The data showed that at P18, the groups that were placed under E.E and tactile stimulation condition performed better than the control group. The subjects of these groups could recall the object after a longer temporal interval compared to the control group. This difference also appeared at P25. From these we can infer that both the treatments have caused an acceleration on the development of the neural circuits which subserve the recognition memory. The effect of early tactile stimulation and E.E were not only strong but also consistent over time, with the subjects performing better compared to the control group even in adulthood. Global-Shape After-Effects Have a Local Substrate David R. Badcock, J. Edwin Dickinson, Renita Almeida and Jason Bell Adaptation to stimuli is a ubiquitous property of the visual system that optimises its dynamic range. It is common to consider the effects of adaptation in the context of the inducing stimuli, e.g. orientation difference between successively-presented lines is exaggerated and an object’s shape appears different after viewing a similar shape; enhancing shape contrast. Orientation and shape adaptation are often thought to arise at different levels of analysis. Here we consider whether adaptation within a substrate of local oriented line detectors results in enhanced shape contrast for similar shapes. We show object specific adaptation of a spatially coincident circle and Cartesian grid. We show that the tilt after-effect predicts local changes in perceived orientation, and that smoothly varying fields of such local effects can account for the global change in perceived shape-even for faces. A shape after-effect will occur in any pattern with modestly different local orientations to the adaptor. Cortical Auditory Evoked Potentials in Response to Alternating Tone-Burst Stimuli Fabrice Bardy,1,2,3 Bram Van Dun,1,3 Harvey Dillon,1,3 Catherine McMahon2,3 and Mridula Sharma2,3 Cortical auditory evoked Potentials (CAEPs) are emerging as an important tool in the evaluation of hearing aid and cochlear implant fitting in infants. Using EEG recording, the aim of this study was to determine whether alternating the stimulus frequency in a sequence of tones with short inter-stimulus intervals (ISIs) would result in an increase in amplitude of the CAEPs. Eleven adults (19-55 years) with normal hearing were investigated using two tone-burst stimuli with frequencies of 500 Hz and 2000 Hz in a fixed or alternating presentation mode with ISIs jittered around 400, 800, and 1600ms in a paired-interval paradigm. In general, the amplitude of the CAEPs elicited by the low frequency tone-burst of 500 Hz are significantly larger (p<0.0001) when compared to the high frequency tone-burst of 2000 Hz. Moreover, the amplitude of the CAEPs significantly increase as the ISI increased from 280 ms to 2240 ms (p<0.0001). Furthermore, the alternation of stimulus frequency increased the amplitude of the cortical response (p<0.01), as also reported by Butler (1968). The increase was most marked for the shorter ISI ranges and for the frequency of 2000 Hz compared to the frequency of 500 Hz. These results suggest that, new neural units at the auditory cortex can be activated by changing stimulus frequency, evoking a CAEP larger than if the frequency of the stimuli is similar. Additivity of Arousal Effects of Caffeine Ingestion and Opening the Eyes Robert J. Barry, Adam R. Clarke and Stuart J. Johnstone Studies indicate that the change from closed to open eyes in a resting condition produces an increase in skin conductance level (SCL) and a global decrease in EEG alpha activity, both indicative of increased arousal. Ingestion of caffeine also produces SCL increase and alpha reduction. As caffeine is widely used by both children and adults, knowledge of the additivity of arousal effects of caffeine and opening the eyes is important in controlling participant state in EEG/ERP studies. EEG activity and SCL were recorded from 22 university students during both eyes-closed and eyes-open resting conditions, under the action of both caffeine and placebo, in a counterbalanced randomised double-blind study. SCL increased significantly from eyes-closed to eyes-open conditions, and from placebo to caffeine, with no interaction. Global reductions in EEG alpha amplitude were apparent with opening of the eyes and caffeine ingestion, again without interaction. Caffeine had a larger effect than opening the eyes on SCL, but this was reversed in alpha. The two dependent measures showed the predicted negative correlation in both eyes-closed placebo and eyes-open caffeine conditions, with the latter substantially reduced relative to the former. Caffeine and opening the eyes have additive effects on two measures of arousal, increasing SCL and reducing EEG alpha. However, the independent variable effects are not equivalent, suggesting that one or both measures reflect additional non-arousal processes. The current results confirm the use of mean alpha amplitude as a measure of resting-state arousal, but also point to non-arousal effects of visual input. Stimulus Relevance as a Determinant of Multisensory Facilitation Ayla Barutchu,1,2 Dean Freestone,2,4 David P. Crewther,3 and Sheila G. Crewther,1 Top-down processes associated with attention and semantic congruity of stimuli are known to modulate multisensory integration at a behavioural and neural level, though little is known about the effects of stimulus relevance on the facilitative effect of multisensory integration. This electrophysiological study explored neural processes associated with stimulus relevance and multisensory facilitation while young adults performed a discrimination task with novel audiovisual associations. Multisensory facilitation of motor reaction times was evident when both components of multisensory stimuli were relevant targets. Changes in event-related-potentials (ERPs) that could be attributed to multisensory facilitation were first observed at the P2 component, lateralised to left central regions. In addition, greater amplitude deflections were observed for the P3 component at parietal electrodes for dual target multisensory stimuli. Induced oscillations in the beta frequency range (14 - 30 Hz) were associated with latency shifts, with late minima peaking earlier for audiovisual stimuli with dual relevant targets than those with irrelevant components at right hemisphere parietal scalp regions. These results provide evidence that, with newly learnt audiovisual associations, stimulus relevance is one determinant of the facilitative effect of multisensory integration on motor actions, and that such behavioral facilitation may be related to changes in neural synchronisation in centro-parietal neural populations. Neurophysiological Modification of Cortical Visual Processing in Young Adults by Omega-3 Fatty Acids: a Randomized Clinical Trial Bauer, I., Crewther, D., Crewther, S., Pipingas, A., Rowsell, R., Cockrell, R., The aim of this study was to investigate the neurocognitive effects of fish oil supplementation. Measures included the Swinburne University Computerized Cognitive Ageing Battery (SUCCAB), and nonlinear multifocal Visual Evoked Potentials (mfVEP). mfVEPs have been previously used to derive the contributions of the fast conducting Magnocellular (M) and the slower conducting Parvocellular (P) neural pathways. Twenty-two healthy participants aged 18-34 were recruited and were administered either a high EPA:DHA (3.3:1) fish oil supplementation (Eye-Q™-Novasel), or a high DHA:EPA (3:1) supplementation (Efalex™-Efamol) in a randomized order. A double-blind, randomized, crossover design was utilized, including a 30-day washout period between two month-long dietary supplementations. It was found that following supplementation with a high EPA:DHA fish oil formula there was a significant reduction in the magnocellular generated second order response. This finding was accompanied by significantly faster choice reaction times. This result is indicative of more rapid neural recovery after firing, and provides the first direct evidence of benefit of a high EPA:DHA fish oil supplementation on neuronal function at the cortical level. Brief Practice in the Go/Nogo Task: Behavioural and Neural Changes Depend on Task Demands Benikos, Nicholas, Johnstone, Stuart J., Roodenrys, Steven. Neural activity underlying executive functions is subject to modulation as a result of increasing cognitive demands and practice. In the present study, we examined these modulatory effects by varying task difficulty, as manipulated by reaction time deadline (RTD), on response inhibition during a single practice session. Sixty participants were assigned to one of three conditions: high (H), moderate (M) and low (L) time pressure, with RTDs of 300, 500 and 1000 ms, respectively, and completed eight blocks of a modified visual Go/Nogo task (70% Go). Task performance and Event-related potentials (ERPs) were examined for condition differences. Overall, participants showed linear decreases in Go reaction time, omission and RTD errors, with the greatest reductions in the H condition. In contrast, inhibition practice effects were dependent on task demands, with only the L condition showing reduced Nogo errors. ERPs revealed decreased N1 and N2 amplitudes across conditions, with the Nogo P3 anteriorisation effect showing incremental decreases with increasing RTD after practice (L > M > H). Overall, these findings suggest that practice-related changes in task performance and brain activity can be modulated by task difficulty and reflected by quantitative neural changes. Perceptual Processing Asymmetry and Hemispheric Resource Competition Jodie Bower and Frances Martin The aim of this research thesis was to investigate differential hemispheric involvement in hierarchical visual perception, emotion perception, and music perception. Additionally, the limited capacity of the two cerebral hemispheres was explored via simultaneous processing of several perceptual tasks competing for resources from the same hemisphere. EEG recordings from 15 musicians and 15 non-musicians were obtained while participants responded to the global/local task (Experiment 1) and a facial affect identification task (Experiment 2), during both music present and music absent conditions. Contrary to hypotheses, there were no significant differences in hemisphere activation between global and local tasks. Contrary to the predicted valence-specific lateralisation, both positive and negative affect faces were processed predominantly within the right-hemisphere. While asymmetry of music perception was expected to depend on musical training, no evidence of this was found in Experiment 1 and only tentative support was obtained from Experiment 2. Although predicted interference effects, resulting from resource competition, were contingent on the unsupported lateralisation hypotheses, simultaneous processing of perceptual tasks did have observable consequences in both behavioural and electrophysiological measures. Therefore, the present experiments exposed the finite nature of hemispheric resources and suggest that both hemispheres have the capacity to be involved in all the above areas of perception. To provide further clarity on the functional roles of the hemispheres, future research investigating the sensitivity of lateralisation expression to experimental conditions such as exposure duration and visual field presentation is recommended. The Role of Fear and Disgust in Contamination Based Obsessive Compulsive Disorder Joshua Broderick & Gabrielle Weidemann Recent research has implicated the emotion of disgust, and particularly disgust sensitivity, in the maintenance and etiology of a number of anxiety disorders, including contamination-based OCD (C-OCD). Recent research has also demonstrated that disgust habituates more slowly than fear in clinical (Mckay, 2006) and high symptom severity analogue C-OCD populations (Olatunji, Wolitzky-Taylor, Willems, Lohr, & Armstrong, 2009). We aimed to improve upon previous research by using physiological measurements concurrently with a self report measure to examine the habituation of disgust and fear to various disgust-eliciting images among participants with high or low C-OCD symptom severity. Method: High symptom severity C-OCD participants (n=35) and low symptom severity C-OCD participants (n=35) were shown six disgust and two neutral images four times each. Participants were required to rate their subjective level of disgust and fear following each image, while heart rate (HR) and skin conductance (SC) were also recorded. Predictions: We predicted that the habituation of disgust would be slower in both groups compared to habituation of fear. We also predicted that the habituation of disgust would be slower in the High C-OCD symptom than in the Low C-OCD group. Finally, we predicted a positive correlation between the physiological and self-report measures Results: Preliminary results provide mixed support for these hypotheses regarding the habituation of fear and disgust in the two groups. Conclusions: Results suggest that disgust has an important function in C-OCD over and above its interaction with fear. Future research will examine the impact of targeting disgust using cognitive restructuring. These findings may have important consequences for the way in which cognitive behavioural therapy is administered to patients with a disgust-related anxiety disorder. A Novel Temporal Window into the Dynamics of Human Cognition Peter G Burton In order to elucidate human higher brain function, a new first-principles model called Cognitive System Theory (CST) has been developed by the systematic application of constraints drawn from our understanding of (i) learning; (ii) experience; (iii) consciousness (as control); (iv) (natural) knowledge; and (v) (acquisition of) the self-model. CST is elucidated in Human Cognition: higher brain function and the science of human consciousness (pp379) {see http://homepage.mac.com/blinkcentral}. CST competently unifies and encompasses the detailed thematic insights drawn from all five thematic analyses. CST gains explanatory power by elucidating how humans develop internalized sequence-management skills (which map nicely onto a computational framework) along with more intuitive vector-targeting capability (which demands a quite different control structure) to transcend mammalian percept-action instrumentality. A compact tri-level framework of homology of operations is found to unify the core learning model of CST, which serves to limit the scope of control required to just two dimensions (a four-way internalized orientation across association areas, coupled with switching between the default (“spotlight”) mammalian form of attention, and two new (exadaptively novel) modes specialized to sequence-management, and vector-targeting, respectively. CST conceptualizes cognitive processing as phasic and phrasic bursts of coherence. Micro-cognitive metrics (MCM) derived from endogenous eyeblinking during structured tasks reveals this temporal punctuation of cognitive processing, to provide a highly objective way of characterizing individual differences in cognitive performance. We are exploring new opportunities for early intervention in areas of learning disability offered by the diagnostic discrimination and case-management & tracking power of blink MCM maps of peer groups. Same Person, Different Medium, Different Face: an Event Related Potential Study Exploring the Influence of Mirrors and Expectations on the Brain Processes Underlying Self-Recognition David Butler, Jason Mattingley, Ross Cunnington, Thomas Suddendorf For decades researchers have used mirrors to study self-recognition in animals and children. However, recent attempts to identify brain processes underlying self-recognition have used pictures rather than mirrors. Here we directly compared self-recognition using pictures and a mirror whilst measuring three Event Related Potentials (ERPs) believed to reflect the encoding and matching stages of face processing (i.e., P100, N170, and P250). We found that these ERPs differed between picture and mirror conditions, raising concerns about the validity of generalizing conclusions from one medium to another. We also examined the role of expectations about what one currently looks like by making participants wear a mask on some trials. ERPs did not differ in response to mirror reflections of self with or without a mask, though they did differ when participants looked at pictures of self and the mask worn by someone anonymous. These results suggest that brain processes underlying self-recognition are influenced by expectations of what one currently looks like, rather than just on their actual facial characteristics. Response-Related Processes: an ERP Investigation of the Impact of Decoding Ability, Task Salience, and Conscientiousness Andrea R. Carr Frances H. Martin The examination of response-related processes has resulted in the identification of a number of event-related potential components that are reliably elicited following a response. This experiment aimed to investigate task salience through incentive and conscientiousness, and the impact of these factors on ERN/Ne, CRN, and early and late Pe and Pc. High and low conscientiousness participants (N = 37) completed a phonological decision task where degree of task salience was determined by various point values assigned to correct responses to tasks. No significant differences in ERN/Ne and CRN amplitudes suggest that task difficulty or stimulus discriminability may influence early response-related processes; however outcomes could also be attributable to task specific factors associated with a language-based task. Evidence of a task salience effect in early and late Pe and Pc indicate that explanations of ERN/Ne in terms of motivational salience may also be applied to late components associated with evaluative processes. Evidence of the influence of conscientiousness at early and late evaluative stages suggest that underlying personality traits, particularly those said to be involved in the regulation of goal-directed behaviour, should be included in explanations of response-related ERP components. Pupil Betrays the Timing of Decisions Olivia Carter, Christof Koch andWolfgang Einhauser The notion of “mind-reading” by carefully observing another individual’s physiological responses has recently become commonplace in popular culture, particularly in the context of brain imaging. The question remains, however, whether outwardly accessible physiological signals can betray a decision before a person voluntarily reports it. In one experiment we asked observers to push a button at any time during a 10-second period (“immediate overt response”). In a series of additional experiments observers were asked to select one number from five sequentially presented digits but concealed their decision until the trial’s end (“covert choice”). In all cases pupil dilation alone predicted the choice (timing of button response or chosen digit, respectively). Given the tight link between pupil dilation and norepinephrine levels during constant illumination, our results have implications beyond the tantalizing mind-reading speculations. These findings suggest that similar noradrenergic mechanisms may underlie the consolidation of both overt and covert decisions. Effects of Recent Exposure to a Conditioned Stimulus on Extinction of Pavlovian Fear Conditioning Wan Yee Macy Chan, Hiu T. Leung, R. Frederick Westbrook, & Gavan P. McNally Considerable research effort has been dedicated to devising means to enhance extinction - the core mechanism of fear reduction in the treatment of anxiety disorders - which is effective but characterised by relapse. Recently, Monfils et al. (2009) found in rats and Schiller et al. (2010) found in humans that a single non-reinforced re-exposure to a fear conditioned stimulus (‘retrieval trial’) prior to extinction training attenuated the recovery of fear. We studied this effect using Pavlovian fear conditioning in rats utilising both between- and within- subject manipulations. Interestingly, a single retrieval trial prior to extinction training significantly augmented renewal and reinstatement of extinguished responding. Augmentation of recovery was not observed if retrieval and extinction training occurred in different contexts. These results contrast with those reported by Monfils et al. (2009) and Schiller et al. (2010).We suggest that these contrasting results could depend on the contrasting influences of either: 1) occasion-setting contextual associations versus direct context – CS associations formed as a consequence of the retrieval trial; or 2) discrimination versus generalisation between the circumstances of conditioning and extinction. The Neuroscience of Personality and Decision Making Ciorciari J and Gountas J Using a multidisciplinary strategy of combining cognitive neuroscience and brain imaging with psychological constructs and marketing principles, two studies explored how personality traits are associated with decision making. The Gountas personality orientation inventory research, (n=6000) suggests that there are four different thinking and information processing styles or decision modes (Gountas et al 2010). Using this and other inventories (NEO-PI and SUEIT), a preliminary study group of 45 participants, had their electroencephalogram (EEG) recorded while watching a series of 24 television advertisements which were based on marketing categories; food & drink, community interests, celebrities and social issues. Preliminary EEG coherence data suggested a neural profile for each personality trait. In fact, findings suggest that that participants with higher emotional intelligence (EI) or lower EI were much more receptive to certain types of advertising material and visual imagery. In a follow-up fMRI study (n=40) of introspective decision making associated with these four personality orientations, imaging data validated the networks detected in the EEG study. The implication of the four corresponding and distinct brain-processing systems which facilitate these “four thinking styles” will be discussed. Non-Linear Visual Evoked Potentials - a Sensitive Assay for Nutraceutical Effects David Crewther, Isabelle Bauer, Sheila Crewther and Andrew Pipingas White noise (random temporal) visual stimulation allows for the temporal structure of visually evoked responses to be studied. In particular, the second order kernel responses give a measure of the degree of neural recovery following stimulation, with an efficient neural system showing smaller second order amplitudes. Examples of non-linear visual responses abound - eg the apparently flicker free light produced by a fluorescent lamp, despite actual flicker of 100 Hz rate. VEP non-linear analysis has been used for a basic understanding of cortical visual processing, delineating separate contributions from the Magno- and Parvo-cellular afferent streams of information. Also, it has recently been used to isolate the physiological differences associated with abnormal visual perception in autistic tendency. Essentially, non-linear protocols provide an extra dimension for analysis of evoked responses than is commonly used. Nutraceutical effects of products, while possibly cognitively beneficial (in terms of behavioural assay), still require evaluation in terms of the possible mechanisms - cardiovascular, metabolic, neural membrane specific, synaptic, and so on. While imaging techniques such as fMRI are informing research, they do not easily separate alterations in cortical perfusion from direct neural effects. Thus we have used non-linear VEP analysis to separate the effects of omega three fish oil preparation. A double-blind, randomized, crossover design was utilized. Following an EPA-rich diet a significant reduction in the magnocellular dominated second order, first slice response was observed. In addition, a significantly different correlation between second and first order amplitudes was found between the two diets, indicative of more rapid neural recovery after firing. Multifocal VEPs as a Measure of Magnocellular Function in Good and Poor Young Readers and Those With Asperger’s Syndrome Sheila Gillard Crewther and David Philip Crewther Although the role of aberrant visual processing and in particular magnocellular processing has long been debated in dyslexia, psychophysical evidence remains divided. Hence we have assessed multi-focal visual evoked potentials (mfVEP) at short interaction times (sensitive to Magnocellular processing) and at longer interaction time (sensitive to Parvocellular processing) in 27 young children (8-12), including 14 normal young readers, 10 poor readers and 3 with Asperger Syndrome. The mfVEP findings have demonstrated considerable difference in physiological function between the three groups. In general dyslexic children showed a ratio of P/M amplitudes that was not statistically different from normal readers, while the Asperger group (AS) was characterized by very well formed M waveforms and a larger latency difference between M and P peaks than similar age controls. The earlier M-pathway response shown by the AS group may indicate the presence of an earlier less mature “magnocellular advantage” allowing less time for attentional processes to be set in place. While no significant latency differences were observed between the DD and N groups, a lower mean P/M amplitude ratio was observed - apparently due to a smaller P evoked response in the DD group. Estimation of Striatal and Extrastriatal Synaptic Dopamine Levels in Healthy Humans Using [18F]fallypride and Positron Emission Tomography Vanessa Cropley, Robert Innis, Pradeep Nathan and Masahiro Fujita Molecular imaging with single photon emission computed tomography (SPECT) or positron emission tomography (PET) can be used not only to measure D2 receptor density, but also to estimate synaptic concentration of endogenous dopamine. Although previous studies have measured synaptic dopamine levels with PET and SPECT in the human brain, most studies have been confined to the striatum due to the availability of suitable radioligands, while studies of drug-induced and tonic dopamine release have not been performed in the same subjects. [18F]fallypride is a high-affinity D2 receptor radioligand capable of measuring D2 receptors in striatal as well as extrastriatal areas of the brain. This study performed [18F]fallypride PET scans at baseline and following oral d-amphetamine and alpha methyl-p-tyrosine (AMPT) in healthy subjects to assess the reproducibility of [18F]fallypride, and, to examine within the same subjects, the effects of amphetamine-induced dopamine release and AMPT-induced tonic dopamine depletion on [18F]fallypride binding in both striatum and extrastriatal areas. Correlations between drug-induced change in binding potential and cognitive performance was also examined. While d-amphetamine significantly decreased [18F]fallypride binding in striatal and several extrastriatal regions (indicating increased dopamine release), depletion of dopamine with AMPT administration did not affect [18F]fallypride binding in any region. D-amphetamine- induced dopamine release was associated with improvement in verbal fluency in the thalamus and substantia nigra regions. Findings from the study indicate that [18F]fallypride has excellent test-retest variability, is capable of measuring stimulant-induced synaptic dopamine release but may be unreliable for estimating basal synaptic dopamine levels, although further studies are required to confirm this finding. Comparing the Reliability of Two P50 Suppression Indices Anna Dalecki, Rodney J. Croft and Stuart J. Johnstone The integrity of ‘sensory gating’ may be assessed electrophysiologically by measuring the reduction of the P50 ERP amplitude in response to the second (S2) of paired clicks (S1, S2). Two metrics, the P50 suppression ratio (S2/S1) and P50 difference score (S1—S2) are used as sensory gating indices. Similarly, two methods are typically used to measure P50 peak amplitudes: peak-to-peak (PP) or baseline-to-peak (BP). Although the S2/S1 ratio is the most commonly used sensory gating index, its reliability is poor. The questions of whether S2/S1 ratio reliability is improved using different peak measurement methods and whether the S1—S2 difference is more reliable than the S2/S1 ratio remain to be resolved. The present study compared S2/S1 ratio and S1—S2 difference reliability, quantified with each of two peak amplitude measurement methods (PP vs. BP) in 20 healthy undergraduates. The S2/S1 ratio was more reliably measured from peak-to-peak as opposed to baseline-to-peak. This relationship was reversed for the S1—S2 difference. Regardless of amplitude measurement method, the S1—S2 difference showed better reliability (ICCPP = .64; ICCBP = .71) than the S2/S1 ratio (ICCPP = .44; ICCBP = .30). The results suggest that the S1—S2 difference may be the more useful metric to use in sensory gating research. The best amplitude measurement method to use to measure S1—S2 and S2/S1 remains an open question. Effect of Exogenous Attention on Early Visual Processing: an Event-Related Potential Study of Facilitation and Inhibition Phases of Exogenous Attention Tharaka Dassanayake, Patricia Michie and Ross Fulham Event-related potential (ERP) research shows that spatial attention can modulate visual processing in extrastriate areas (P1 and N1 components). This attentional facilitation seems to depend on perceptual load, cueing condition (exogenous/endogenous) and cue-stimulus onset asynchrony (SOA) (facilitation at short SOAs and inhibition at long SOAs). Supported by the findings of two recent ERP studies, we hypothesized that exogenously-cued high-perceptual-load stimuli presented in optimal locations for an individual may elicit an attentional facilitation at even earlier stages of processing (as reflected by C1 component generated in striate cortex) at short SOAs but not at long SOAs. To test this hypothesis, we conducted a two-stage ERP experiment on 15 healthy females (age 19-57years). First, a Probe Task was administered to characterize two optimal stimulus locations and the scalp site that generate the most prominent C1 component in each individual. In the subsequent Spatial Attention Task, the subjects performed a choice reaction task for stimuli presented in the two optimal locations under two exogenous cueing conditions (valid vs. invalid) and two SOA conditions (170ms vs. 1000ms). The effects of cueing validity and SOA on reaction time (RT) and C1 component of the pre-determined scalp location were examined. RT data showed a significant validity*SOA interaction, with a significant attentional facilitation in the short-SOA condition (p<0.001) but not in the long-SOA condition (p>0.05). However, direct comparison of the grand average ERP waveforms did not show significant attentional enhancement of C1 amplitude. The findings of further analysis of behavioural and ERP data will also be discussed. The Psychometric Properties of Mismatch Negativity (MMN) Matthew Davidson and Rodney J. Croft The amplitude of the Mismatch Negativity (MMN) component of the auditory event-related potential (ERP) is elicited by deviant changes in a homogenous stimulus sequence. The component has repeatedly been shown to be reduced among schizophrenic patients compared to healthy controls, yet a number of unresolved methodological issues limit the clinical utility of the measure. Unresolved issues include the unestablished reliability of the component, unknown effects of deviant difficulty and the effect of attention on the MMN task. In order to address these issues, twenty-two healthy participants’ MMN responses were measured during attended and unattended conditions after calibrating deviant difficulty based on each participants’ discrimination ability. Results indicate good within-session reliability only for MMN responses elicited following the attended easily discriminated deviants (ICC = .65); and a significant effect of deviant difficulty on the amplitude of MMN responses (p < .001). The present results suggest that prototypical MMN elicitation procedures are not optimized, and could be improved by calibrating easy deviant difficulties for the elicitation of MMN during an attended task. Pre-Stimulus Low Frequency Activity and ERP Component Amplitudes Frances M. De Blasio and Robert J. Barry Our current understanding of electroencephalographic activity (EEG) contributions in the genesis of the event-related potential (ERP) components is deficient. Recent findings indicate a complex and dynamic contribution pattern, seemingly modulated by EEG frequency, ERP component, and stimulus-specific task requirements. Preliminary insight into the extent of the contributions from each of the EEG bands in the generation of the ERP, and their influence on each component, is yet to be systematically verified. The low frequency bands appear to be significantly implicated in the genesis of the five major auditory ERP components (P1, N1, P2, N2, LPC/P3) across stimulus conditions. This investigation thus employed an equiprobable auditory Go/NoGo task to explore the nature of the relationship between the pre-stimulus activity in the Delta and Theta bands and the ERP component amplitudes across two presentation blocks. Successful Go and NoGo trials for twenty participants were sorted at nine electrode sites (F3, Fz, F4, C3, Cz, C4, P3, Pz, P4) according to pre-stimulus RMS EEG activity at Cz for each band. Site ERPs were derived from the upper and lower thirds of the sorted trials for each stimulus condition and block. The complex of results are largely consistent with, and clarify, previous findings. For example, higher pre-stimulus Delta resulted in significantly more positive amplitudes across four of the five ERP components; moreover, the Delta-ERP patterning of significant relations deviated from that of the Theta band. These findings support the differential nature of EEG-ERP contributions and are discussed in respect to ERP genesis. Investigating the Interplay Between Sensorimotor Gating and Emotional Processing Racheal Degabriele, Jim Lagopoulos, Philip Ward Electrophysiological research investigating the nature and timing of cognition in humans often involves paradigms that incorporate unimodal stimuli. In particular, studies of sensory gating typically only employ auditory click stimuli. However, humans rarely perceive auditory stimuli independently in the environment and evidence suggests the brain may preferentially process multimodal stimuli. The current study sought to investigate the mechanisms underpinning the processing of auditory stimuli when influenced by visual cues. Using a multimodal sensory gating paradigm, subjects viewed face stimuli (depicting either disgust or neutral expressions) immediately prior to the standard auditory dual-click stimuli. Twenty-two age- and sex-matched healthy volunteers were presented with 84 face stimuli immediately prior to the onset of S1 and S2 auditory click stimuli (frequency=1000Hz, duration=1ms, ISI=500ms). Electrophysiological data were obtained from 28 channels and the data presented was analysed from Cz. The results indicate significant amplitude suppression to the S2 stimulus for P50, N100 and P200 ERP components. A main effect for emotion and a stimulus by emotion interaction was also found for P200 amplitude. Specifically, S1 evoked a reduced response for the disgust (M: 11.05µV, SD: 5.90) compared to neutral condition (M: 12.88µV, SD: 6.56). However, both emotions evoked similar responses to S2 (Mean: 6.77µV, SD: 3.63), (Mean: 6.87µV, SD: 3.72). Results demonstrate that the P200 amplitude elicited by S1 was preferentially decreased for disgust and this resulted in decreased sensory gating compared to neutral (t(21)=2.110, p=0.047). These findings may reflect a compensatory mechanism to the disgust emotion such that increased resources are allocated. Insight into the Absence of Empathy After Severe Traumatic Brain Injury A deSousa, S McDonald and JA Rushby Severe traumatic brain injury (TBI) often leads to marked difficulties in the domains of empathy, emotional responsivity, and social behaviour. However, the relationship between domains, if any, is unclear. The present study addressed this question in a sample of 21 participants with severe TBI and 25 controls. Six film clips containing pleasant, unpleasant and neutral content were presented whilst facial EMG and skin conductance (SC) were measured. Self-reported emotional empathy questionnaires, and a range of neuropsychological tests were also administered. A close relative of each TBI participant completed the Current Behaviour Scale (CBS) to assess for changes in emotional control and drive occurring as a consequence of the injury. In comparison to control participants, those in the TBI group displayed a reduction in the ability to empathize emotionally. Further, TBI participants showed an impaired pattern of facial mimicry to both pleasant and unpleasant films. They also exhibited lowered autonomic arousal, particularly to unpleasant films. Despite failing to find a relationship between emotional empathy and physiological responding, relative reported loss of drive was significantly related to poor empathy, whereas, loss of emotional control was associated with heightened empathy levels in this population. The results suggest that level of emotional empathy post injury is associated with disorders of drive or control. This has important implications for understanding and treating empathy deficits following TBI. Can We Get a NoGo N2 Effect With Auditory Stimuli? Kelly M. Douglas and Janette L. Smith The N2 and P3 are putative markers of inhibition in the Go/NoGo task. If this is the case, they should be unaffected by stimulus presentation modality. Since Falkenstein et al. (1995), the dogma has been that no N2 NoGo effect can be observed with auditory stimuli. However, Nieuwenhuis et al. (2004) showed that a lack of effect may be due to low perceptual overlap between the Go and NoGo stimuli traditionally used by Falkenstein’s group. This study examined the N2 and P3 NoGo effects elicited by five sets of auditory stimuli: different tones (1000Hz and 2000Hz), similar tones (1000Hz and 1100Hz), different letters (‘F’ and ‘J’), similar letters (‘F’ and ‘S’), and novel sounds (bird whistle and frog croak). The N2 NoGo effect was significant for similar and different letters, and for similar tones, with the effect for different tones approaching significance. As expected by the perceptual overlap hypothesis, the largest N2 NoGo effect was observed with the similar letters. In contrast, the P3 NoGo effect was significant and of a similar magnitude for all stimulus sets. The differential effect of the stimulus sets on the two components suggests separable underlying processes reflected in N2 and P3. Social Cognitive Impairments in Autism Spectrum Disorders: Insights from Neuropsychiatry Peter G. Enticott,1,2 Hayley A. Kennedy,1 Nicole J. Rinehart,2 Scott May,1 Autism spectrum disorders (ASD) are a group of neurodevelopmental conditions that are characterised by social, communicative, and behavioural impairments. The neurobiological basis of ASD is unclear, and there are no validated biomedical treatments targeting the core symptoms. Recent developments in the social cognitive neurosciences, however, have provided important insights into possible underlying neural mechanisms. One such model centres on the so-called mirror neuron system (MNS), which refers to brain cells and brain regions that appear to simulate what is happening in the brain of the person we are observing. The MNS has been implicated in a range of social cognitive abilities, including facial affect recognition and theory of mind. Our research involving transcranial magnetic stimulation (TMS) and functional magnetic resonance imaging (fMRI) in autism appears to support the idea that mirror neurons may contribute to social cognitive impairments in ASD; individuals with ASD reveal a vastly atypical pattern of MNS activation (both reduced and differential activation) when compared with control participants. While this provides crucial information about the possible brain basis of social cognitive impairments in ASD, and may inform as to a broader underlying neural mechanism, it also provides an opportunity to develop treatments for these impairments using cutting-edge brain stimulations techniques. “Shut Up” an Electrophysiological Study Investigating the Neural Correlates of Vocal Inhibition Andrew C Etchell, Paul F Sowman and Blake W Johnson Event-related potential (ERP) correlates of manual response inhibition have been described in detail. However, to date there are no ERP studies of vocal response inhibition. Observations from clinical pathologies suggest there are substantial differences between the inhibitory systems that control the face and the hands. The present study identified ERP correlates of vocal response inhibition and compared them to those from manual inhibition. ERPs were recorded for 15 subjects who performed both a vocal and a manual version of the stop signal task. Behavioural data indicated that subjects were able to inhibit vocal responses within 334ms. Cluster-based permutation analysis revealed a 300ms ERP component that was significantly larger (p<0.05) in amplitude for trials in which participants successfully inhibited a response as compared to ignore signal trials (a trial matched for visual stimulation and frequency but where inhibition is not required). When comparing the difference between stop and ignore trials for manual and vocal modalities, greater activity was also observed over the speech motor area on vocal failed stopping indicating a failed effort to maintain a low level of excitability. Future research will use this ERP approach to study disorders of inhibitory vocal control such as stuttering. Age-Associated Cognitive Decline: an Investigation of the Speed/Accuracy Trade-Off Erin Fogg With the population aging steadily and with a corresponding increase in the incidence of dementia, there is a need for more sensitive measures of cognitive decline. In a previous study which utilised time limited tests of fluid intelligence, marked changes in performance accuracy and speed of response were found; however, the study failed to account for speed/accuracy trade-offs that have been well documented in cognitive aging research. The present study aimed to address these limitations by comparing cognitive changes across the lifespan in response to both time limited and unrestricted task timing. It was envisaged that by removing time pressure, older individuals would sacrifice speed to maintain greater accuracy. Ninety six healthy volunteers 20 to 85 years completed nine computerised cognitive tasks. The accuracy versus age regression did not change with unrestricted timing in comparison to the previous restricted version, however, speed of response versus age task gradients increased significantly. Furthermore, an overall performance measure combining speed and accuracy was found to decline significantly with age on all tasks domains and these changes were independent of the nature of task timing. These results indicate that while speed/accuracy trade-offs may exist, the majority of ‘fluid’ cognitive tasks investigated, particularly immediate recognition memory and spatial working memory continued to be robust measures of cognitive decline. A better understanding of tasks that are more sensitive indicators of decline is useful in detecting subtle changes with age that also have the potential to be ameliorated in pharmacological and neutraceutical intervention research. Decision Making and Personality Characteristics in High Functioning Substance Users James Gooden, Daniel Upton, Siyun Tan, and Julie Stout Decision making deficits have been consistently observed in severely affected substance users, however less is known about the decision making and personality characteristics of high functioning substance users. This study incorporated a multi-method approach including behavioural measures, cognitive modelling, and self-report questionnaires to characterise high functioning, predominantly university student, substance users. Ninety one participants comprising controls, moderate and heavy substance users were recruited. Participants completed a range of personality questionnaires and a simulated gambling task (IGT). We also used cognitive modelling techniques to investigate the underlying cognitive processes of decision making on the IGT. We found that substance users and controls performed equally well on the IGT, with no differences in the cognitive model parameters. For the personality measures, however, we found that substance users were more impulsive, fun seeking, driven to obtain goals, and less sensitive to punishment than controls. Our results also indicated that performance on the IGT was related to a measure of behavioural inhibition in heavy users. Consistent with previous research, we concluded that high functioning substance users exhibit differences in personality characteristics but not deficits in decision making. Furthermore, our results suggest that in groups with strong reward seeking behaviours, personality characteristics such as behavioural inhibition become important for regulating behaviour on the IGT. These results have implications for understanding how cognitive and personality factors may relate to substance use behaviour. Static and Dynamic Modulated ERP Correlates of Emotional Expressions in Adult Average and Above Average AQ Groups Peter Goodin, Jordy Kaufman and Patrick Johnston This study examined the N170 and other ERP components in the right temporo-occipital cortex to determine if modulation occurred through dynamic and static displays of emotional expression, or by Autistic-like traits measured with the Autistic-Spectrum Quotient test. Electrophysiological activity was recorded from 21 participants, with results determining no change to the N170 based on either motion of presentation stimuli or group. Unexpected components were discovered following the N170, a split in motion amplitude followed by a distinct amplitude difference between Average and Above Average groups. It was thought the motion split was due to differing cortical processing of static and dynamically presented emotional stimuli. The group difference supports the construct of Autistic-like traits and was thought to be caused by alterations in the Contingent Negative Variation. Does Visual Stimuli Assist in Understanding Speech in Noise in Children? - an EEG and MEG Study Pia Gyldenkaerne,1,2 Mridula Sharma,1,2 Suzanne Purdy,1,3 Melanie Reid,1,2 It is commonly recognised that visual cues can enhance speech intelligibility in quiet as well as in noisy listening environments. It has been shown that visual cues can improve speech perception in noise and that the improved signal-to-noise ratio may be perceived to be as much as 15 dB (Sumby, 1954). Children with auditory processing disorders are a heterogeneous group (ASHA, 1996; Chermak, 2002; Ramus et al., 2003; Sharma, Purdy, & Kelly, 2009) and are described as having listening difficulties, e.g. difficulties listening in noise and one of the main interventions recommended for this population is addition of visual cues; however, audiovisual integration is not well understood at a cortical level. This study aims to investigate the effect of visual cues on auditory perception of speech in noise in children (7-12 years) with and without auditory processing disorders. Cortical evoked potentials (CAEPS) were recorded using electroencephalography (EEG) and magnetoencephalography (MEG) in response to the natural speech token /ba/ presented as unimodal (auditory only and visual only) or bimodal (audiovisual) stimuli and at two different signal-to-noise ratios (+3 dB and +10dB). Results show that elevated noise levels have a detrimental effect on responses to unimodal auditory stimuli, but that the addition of visual cues results in robust auditory evoked responses at both noise levels. Improvement of Error Awareness and Modulation of Error-Related BOLD Activity via Single-Dose of Methylphenidate in Healthy Adults Robert Hester,1 L. Sanjay Nandam,2 Joe Wagner,2 Pradeep J. Nathan,3 Jason B. Mattingley,2 and Mark A. Bellgrove,2 Poor detection of errors has been linked to clinical symptoms including the loss of insight, deluions and perseverative behaviour, in conditions such as schizophrenia and drug addiction. These conditions share alterations in monoamine signalling that may influence the neural mechanisms underlying error processing, however our understanding of the neurochemical drivers is limited. We conducted a randomized, double-blind, placebo-controlled, cross-over design of the influence of selective dopamine (methylphenidate), noradrenaline (atomoxetine) and serotonin (citalopram) reuptake inhibitors on error awareness in 24 healthy participants. The Error Awareness Task, a Go/No-go response inhibition paradigm, was administered to assess the influence of monoaminergic agents on errors that the participant was either aware or unaware of committing and the associated event-related fMRI changes. Methylphenidate was associated with a significant improvement in error awareness, but not response inhibition accuracy or speed, in comparison to placebo and either atomoxetine or citalopram. Methylphenidate also significantly influenced BOLD activity arising from the anterior cingulate cortex and bilateral inferior parietal regions, with moderate increases in aware error activity and large decreases in unaware error activity when compared to the placebo condition. These data suggest dopamine may aid attention to task, thereby setting ideal conditions for promoting awareness of one’s errors. ‘Vision for Action’ Enables Volitional Control of Binocular Rivalry Laila Hugrass and David Crewther Binocular rivalry is a form of perceptual bistability that occurs when different images are presented to the two eyes. The current consensus is that perceptual switches are spontaneous, obligatory and cannot be performed by dint of will power. We have discovered an exception to this rule: observers can switch voluntarily between rivaling percepts that are coupled conflicting visuomotor responses, such as optokinetic nystagmus. We compared the ability initiate voluntary perceptual switches in response to auditory cues during rivalry between apparent motion (AM), drifting (D) and stationary (S) grating pairs, against a monocular control condition (M), where drifting gratings were exogenously switched between the two eyes. For the AM and D conditions, commands to perceive the suppressed motion resulted in an immediate switch in perceptual dominance. Concurrent switches in direction of optokinetic nystagmus verified this result. In contrast, voluntary control was relatively weak in the S condition. Reduced saccade probability under conditions of voluntary control indicates that saccades were unlikely to have triggered perceptual switches. However, the results of follow up experiments suggest that ocular pursuit contributes to top-down control over rivalry between drifting gratings. Hence, while our findings might appear at first as a triumph of mind over brain, they are perhaps better characterized as the synergy of the neural representations for perception and action resolving competition for awareness. Cognitive and Neurocognitive Training Effects in Children With and Without AD/HD Stuart Johnstone, Ellie Johnston, Russell Blackman and Steven Roodenrys This study assessed whether 25 sessions of combined working memory (WM) and response inhibition (RI) training could improve overt behaviour, cognitive task performance, and resting eyes-closed electroencephalography (EEG) in children with attention-deficit/hyperactivity disorder (AD/HD). Children without AD/HD were also included to examine whether training benefits could transpire in the absence of pre-existing deficits. There were 3 training conditions, with approximately equal numbers of AD/HD and non-AD/HD participants; cognitive training only (SW), cognitive training with the addition of attention-monitoring and feedback (SW-AM) and waitlist (WL). Tasks measuring the function of RI and WM, as well as related but non-trained executive functions (EF), and frontal resting EEG were completed pre- and post-intervention, by 60 children with AD/HD and 68 healthy controls. Additionally, parents completed behavioural questionnaires at these sessions. Children with AD/HD who completed the training demonstrated decreased cognitive/inattentive and DSM-IV based AD/HD symptoms, which corresponded to changes in frontal resting EEG. Results indicated that RI and WM training performance was improved post-training for children with and without AD/HD in the SW condition. Generalisation of improvements to non-trained tasks also occurred for some tasks. It was concluded that combined WM and RI training has potential as a complementary treatment option for AD/HD, with possible benefits for children without pre-existing deficits. Relationship Between White Matter Lesions and Cognitive Motor Functions in Older Adults Todd Jolly, Frini Karayanidis, Patricia Michie, Christopher Levi, Mark Parsons, Grant Bateman and Peter Schofield Cortical atrophy, White Matter Lesion (WML) formation as well as microscopic changes within white matter tracts are all related with advanced ageing and presumably underlie the cognitive and motor changes associated with ageing. Studies that focus on the relationship between white matter lesions and cognitive functioning have produced highly discrepant findings, likely due to variations in spatial resolution of imaging protocols and the use of broad neuropsychological tests that are insensitive to specific deficits of Executive Functioning (EF). We present early pilot data from a research program that aims to map how location and severity of white matter pathology relate to deficits in cognitive functioning in healthy ageing. We use lesion segmentation, diffusion tensor tractography, as well as flow quantification protocols on high resolution (up to 1mm isotropic voxels) MRI scans, thereby enabling accurate white matter and vascular profiles for each individual. We include a detailed neuropsychological assessment targeting memory, attention and executive functioning processes. In addition, we implement experimental cognitive paradigms which tap into specific components of EF (working memory, shifting and inhibition) to derive behavioral measures of EF performance, electrophysiological measures that provide fine temporal information about underlying neural processes and functional MRI measures that provide accurate information regarding the brain areas that support these EF processes. Relating behavioural and brain activation measures derived from these paradigms with structural brain changes with ageing will provide new insights into the pathophysiological sequelae of cerebral WML. Integrating Across Behavioral Modeling and Electrophysiological Measures to Study the Temporal Dynamics of Cognitive Control Processes F. Karayanidis, E. Mansfield, L.R. Whitson, A. Heathcote and P.T. Michie Goal-directed behavior is an aspect of executive control that requires both the ability to maintain focus on a single goal and to switch attention among alternative goals. The task-switching paradigm experimentally manipulates strategic and automatic processes that affect advance preparation for, and implementation of, a switch or repeat in task. ERP studies implementing the cued-trials paradigm can temporally dissociate the relative contribution of preparatory and target-driven processes on task-switching performance by providing control over the onset and duration of the preparation interval. Recent electrophysiological studies have identified ERP components associated with preparatory and target-driven control processes, while evidence accumulation models (e.g., Wagenmakers et al., 2007, Psychon. Bull. Rev. 14, 3–22) have been applied to characterize decision making processes during task-switching. Our work integrates across these two approaches in order to characterize the temporal dynamics of cognitive control processes affecting task-switching performance. We present data from two studies using distinct paradigms in young adults (Karayanidis et al., 2009, Cogn. Affect. Behav. Neurosci. 9, 202–215) and an adult lifespan sample (Whitson et al., in preparation). We show that ERP components time-locked to preparatory control processes are associated with variations in response criterion setting and task reconfiguration, whereas ERP components time-locked to target-driven control processes are associated with rate of evidence accumulation. We conclude that the integration of behavioral and neuroscientific methodologies is critical to understanding the complex nature of cognitive control processes (Karayanidis et al., 2010, Front. Psychology 1:25. doi:10.3389/fpsyg. 2010.00025). Memory Processes Marked by Sub-Millisecond Fluctuations in Neural Transmission Jordy Kaufman, Antanita Chrysostom, Angela Mayes, Richard Silberstein and Andrew Pipingas The “binding problem” posits that because cognition is achieved through processing in separable neural pathways, the brain requires a mechanism to recombine this information so that the output of each of these pathways are correctly assigned to the proper thought or concept. A popularly proposed mechanism for such synchronisation involves gamma oscillatory activity (i.e., neural activity in the 40 Hz range). Electrophysiological studies of 40 Hz activity in adults, infants and animals have led to the intriguing finding that gamma appears to increase when an individual is engaged in a cognitive task. Nonetheless, widespread scientific acceptance of gamma as a mechanism for binding is unlikely due to an opposing body of literature suggesting a more mundane explanation for this increase in gamma. Specifically, EMG (electrical activity generated from outside the brain) is known to masquerade as EEG. Recent studies suggest that such muscle activity might account for a significant amount of what is often interpreted as cognition-related gamma. Here we present data from a steady state topography (SST) study that validate and extend our understanding of the gamma/binding relationship. We propose that binding processes underlying cognition may be signaled by sub-millisecond variations in neural firing rate. The SST methods employed here are particularly sensitive to such fluctuations compared with more traditional time-frequency analyses. Psychophysiological Indices of Inclusion Versus Exclusion During the Cyberball Task Michelle Kelly, Skye McDonald and Jacqueline Rushby Recent imaging research indicates that the brain regions associated with the pain of ostracism are the same as those associated with physical pain. However, research has not extended to examine the effects of ostracism on the autonomic nervous system. In fact, the majority of research on ostracism has relied on self-report data. This study aimed to examine the autonomic response to the experience of inclusion and ostracism using the Cyberball task. Participants ostensibly play a ball-tossing game over the internet with two other participants, however, in reality the other players are programmed to either include or exclude the real participant from the game. Data are presented for 42 (14 male) undergraduate students who participated in both an inclusion and ostracism condition. Order was counterbalanced across participants. Differences in arousal (examined with skin conductance levels (SCLs)) and attention (examined with heart rate (HR)) were compared. When participants were included, there was a marked decrement in arousal over the course of the task, whereas there was no evidence of habituation when participants were ostracized. These results do not appear to be due to differences in attention as HR changes did not differ between the inclusion and ostracism conditions. The implications of these results are discussed for specific clinical populations who are known to have impaired autonomic responses, and who are often ostracized from society. Cognitive Function, Oxidative Stress and Inflammatory Markers Among Heart Failure Patients Christina Kure, Franklin Rosenfeldt, Con Stough, Andrew Scholey, Andrew Pipingas, David Kaye, Peter Bergin and Stephen Myers Background: Cognitive impairment (CI) is common in heart failure (HF), especially in older patients. CI may reduce the patient’s ability to understand and comply with therapeutic regimes, increase hospital re-admissions and mortality rates. Understanding the mechanisms associated with CI in HF may facilitate development of interventions to potentially preserve cognitive function at various stages of the condition. Previous research indicates that CI may be underpinned by changes in cerebral blood flow (CBF), however the effects of inflammation and oxidative-stress have not been investigated. Objective: To investigate whether inflammation and oxidative-stress are associated with cognitive impairment in older HF patients. Methods: Well established measures of memory, attention and mood were administered to HF patients and a healthy control group matched for age, sex and IQ. Biochemical measures included high sensitive C-reactive protein (hsCRP), biological antioxidant potential (BAP), determinable reactive oxygen metabolites (d-ROM), CBF (measured using Doppler ultrasound) and arterial stiffness. Results: To date 23 of a projected 30 HF patients (66.61±6.13 years; 70% male; NYHA class II-III) and 38 healthy controls (67.13±5.29 years; 53% male) have completed the study. Preliminary results show that patient’s d-ROM levels were significantly higher (454.57 ±71.83) than healthy controls (353.84 ±85.14), F(1,41)=15.24, p=<0.001. Furthermore, in patients hsCRP was significantly correlated with the following subscales of Profile of Mood States: depression/dejection (r=.548, p=.012); vigour/activity (r=-.538; p=.014) but not in controls: depression/dejection (r=.079, p=.721), vigour/activity (r=-.321; p=.136). Conclusions: Oxidative stress and inflammation in HF may contribute to depression and reduced vigour, potentially leading to novel therapeutic regimes. Oxytocin Attenuates Amygdala Response to Fear in Social Anxiety Disorder Izelle Labuschagne,1 K. Luan Phan,2 Amanda Wood,3 Phyllis Chua,1 Background: The neuropeptide oxytocin plays an important role as a mediator of pro-social and anxiety-related behaviours. The amygdala is thought to be a critical role in oxytocin’s actions as well as in modulating these behaviours. We examined the effects of oxytocin in healthy controls (CON) and patients with Generalised Social Anxiety Disorder (GSAD), in which amygdala threat/fear-related hyper-sensitivity is a cardinal pathophysiological feature. Methods: In a functional magnetic resonance imaging study utilising a double-blind placebo-controlled within group design, the acute effects of intra-nasal oxytocin (24 I.U or 40.32 micrograms) relative to placebo was examined on amygdala reactivity to social visual cues in 18 GSAD and 18 CON male participants. Results: Under placebo, both groups activated bilateral amygdala to emotional faces, and GSAD patients exhibited greater reactivity to fearful faces in bilateral amygdala, relative to CON (Left, t=3.04, p=0.009 SVC; Right, t=2.12, p=0.06 SVC). In both CON and GSAD groups, amygdala activation to fearful faces was greater in the placebo session than in the oxytocin session (CON: Right, t=3.69, p=0.01 SVC; GSAD: Left, t=2.64, p=0.04 SVC). Following oxytocin administration, amygdala reactivity in GSAD patients was similar to that of CON subjects on placebo. In addition, the extent of reduction in amygdala reactivity to fearful faces by oxytocin was associated with an increase in subjective relaxation. Conclusions: These findings suggest an inhibitory effect of oxytocin on amygdala response to fear and suggest that oxytocin may be an efficacious treatment strategy for anxiety disorders such as GSAD, marked by fear-related behaviour and amygdala hyper-reactivity. Exploring Attention and Working Memory With fMRI Gemma Lamp,2 Bonnie Alexander,2 Andrea Sanchez-Rockliffe,1 Sheila Crewther,1 and David Crewther,2 Behavioral and fMRI techniques have been utilized to investigate the neuroanatomical correlates of goal directed attention in working memory n-back tasks. It was hypothesized that two different task types, one visuo-spatial and one facial recognition, would demonstrate different hemispheric lateralization. Furthermore, when comparing activation by gender for each task type, females were hypothesized to be largely left hemisphere dominant, while males were expected to show largely right hemisphere activation. A further analysis comparing target to non-target activation for each participant (Single subject event-related functional magnetic resonance imaging [ER-fMRI]) was hypothesized to reveal a network of frontal and parietal sites, similar to Corbetta’s visual attention networks, with a significant positive correlation between the accuracy level for each task and the strength of the signal contrast between target and non-target activation. One task used highly familiar cartoon faces of varying colour and emotional expression, expected to primarily activate the left hemisphere, while the second task was expected to activate the right hemisphere, using 3-D cubes with 0, 45 or 90 degree rotations. The 1-back design required manipulation, continuous updating and selective attention, with each task type requiring different button presses to differentiate repeat and non-repeat responses. The block designed and ER-FMRI results both demonstrated fronto-parietal networks of activation, with the ER-FMRI analysis demonstrating activation predominantly in the left hemisphere for both tasks differing, with respect to stimulus class and across individuals. As expected, a gender difference was apparent with females demonstrating largely left hemisphere activation, however males demonstrated more bilateral activation across tasks. Furthermore, male performance was superior in the visuospatial task and female performance was superior in the facial attributes task. No correlation was observed between the strength of activation and task accuracy. Increasing difficulty of the mental rotation 1-back task appeared to activate a bilateral network of areas with greater bilateral parietal than frontal activation. The facial attributes tasks activated largely left hemisphere dominant frontal areas. Neurophysiology of Compulsive Buying: a Preliminary Study Lee Lawrence, Joseph Ciorciari and Michael Kyrios The behavioural and cognitive phenomena associated with Compulsive Buying (CB) have been investigated frequently, but it’s neurophysiology has received less attention. Using substance addiction as an analogy, aspects of the neurophysiology of CB in executive processing, and cue-reactivity were investigated. 24 participants (M = 25.38, SD = 7.02) from a general population completed a visual Oddball paradigm, as well as a memory task with shopping items used as a cueing paradigm - participants rated their urges to buy shopping items after this memory task. Participants were separated into high and low CB symptoms, and analyses were performed on the P300 and alpha coherence’s for, and in a preferred, non-preferred, and preferred minus non-preferred item condition across numerous locations. The P300 was also analysed for the Oddball detection task at a central site. Manipulation checks were performed with mania and urges to buy. Greater activation was found in dorsal and ventral processing routes, left central and frontal areas for EEG coherences. A significant positive, left frontal P300 for those with greater CB tendencies was found in only the preferred minus non-preferred item condition. There were no significant differences in the Oddball paradigm. Different neurophysiological patterns exist with CB phenomena reflecting cue reactivity and perhaps episodic memory from increased arousal and attachment to items. The Contribution of Dorsal and Ventral Visual Areas to Object Recognition Robin Laycock, Bonnie Alexander, David Crewther and Sheila Crewther The dorsal and ventral visual stream dichotomy has been the subject of extensive amounts of research and yet remains an area of some controversy. The ventral stream is understood to be responsible for visual perception, and object processing. The dorsal stream, however, appears more difficult to pin down. Recent models of visual processing have highlighted the role of the dorsal stream in driving bottom-up attention networks to facilitate later detailed object processing in the ventral stream. We sought to investigate the timing of necessary processing in the lateral occipital cortex (LO) in the ventral stream, extrastriate dorsal stream area V5, and the temporoparietal junction (TPJ, a parietal area suggested to be involved in salience detection within a ventral parieto-frontal attention network, and a potential candidate for the termination point of the dorsal stream. Transcranial Magnetic Stimulation (TMS) was used to target either LO, V5, TPJ and a control site (vertex) at three target onset latencies, using paired pulses with 50ms inter-pulse intervals (i.e., 0,50; 100,150; 200,250ms onset latencies). Participants completed an object recognition task with two conditions: Abrupt contrast onset/offset, which was expected to tap into dorsal stream attention networks, or alternatively ramped contrast onset/offset, which was not expected to be well-suited to activating bottom-up attention networks. Preliminary data showed different temporal patterns of activation between dorsal and ventral stream sites, which are interpreted in terms of more recent understandings of the visual processing. Single-Trial Event-Related Potentials, Autonomic, and Eye-Movement Responses to Monaural Tones in an Orienting Reflex Context Brett MacDonald and Robert J. Barry Elicitation and habituation of the Orienting Reflex (OR) were investigated using single-trial event-related potentials (ERPs) recorded at 19 EEG sites, skin conductance (SC), and heart rate (HR). Comparisons were made between the S-R patterns of these measures in terms of their conjectured stage of OR processing. Participants were presented with 8 unexpected innocuous novel tones to one ear at very long variable inter-stimulus intervals. Horizontal eye-movement in the direction of the ear of stimulation was taken as a behavioural measure of the OR. Single-trial ERPs were decomposed using Principal Components Analysis for intervals covering the early N1 complex and the late positive complex (LPC). Significant directional differences in eye-movements with the ear of stimulation were evident at trial 1, with this difference reducing over trials, providing evidence of OR elicitation and habituation. Electrodermal responses, Processing Negativity, and the Novelty P3 showed substantial decrement with trials, indicating close links to the OR. HR deceleration and N1 Component 1 did not systematically change over trials, linking them to transient stimulus onset processes. N1 Component 3, P3a, P3b, and early and late Slow Waves showed only topographic changes over trials without substantial decrement, precluding them as OR indexes. These results highlight the value of a sequential-processing approach to the OR, aligning preliminary processing stages with autonomic, central, and behavioural measures in simple paradigms with very long inter-stimulus intervals. Intensity and Novelty Effects on Central and Autonomic Responses to Auditory Stimuli in a Task-Free Habituation Paradigm Brett MacDonald and Robert J. Barry Furthering our investigations of the Orienting Reflex, autonomic and central response patterning in a passive auditory habituation task was explored by varying stimulus intensity and novelty. Sixteen 1000 Hz tones at 60/80 dB, of 50 ms duration with 15 ms rise/fall times, were presented in an alternating sequence with random ISIs between 45 and 70 s, without any task requirements. Start intensity was balanced between subjects (N = 16). The evoked cardiac response (ECR), respiratory pause (RP), and the skin conductance response (SCR) were extracted for each stimulus. Single-trial ERPs from 19 sites, specifically the N1 and the Late Positive Complex (LPC), were estimated at each trial in EOG-corrected data. Each response measure was analysed in a factorial design examining intensity and trials effects. The ECR, a simple heart rate deceleration, was unaffected by intensity or trials. RP decreased over trials, but showed no intensity effect. SCR reflected stimulus intensity and showed significant decrement over trials. N1, with a midline centro-parietal distribution, showed greater responses overall for louder tones, in particular centrally, with no decrement over trials. The LPC, with a centro-parietal distribution, was insensitive to intensity, with some evidence of a frontal decrement over trials. Topographic interactions in the N1 and LPC suggest that different subcomponents in these are differentially sensitive to stimulus intensity and novelty (N1 and LPC, respectively). These results are discussed in the context of Preliminary Process Theory, a sequential-processing model of the Orienting Reflex. The Effects of Multivitamins on Cognition and the Steady State Visually Evoked Potential (SSVEP) in the Elderly Helen Macpherson, Andrew Pipingas, Richard Silberstein and Kathryn Ellis Evidence from population studies indicate dietary intake, or blood levels of the B vitamins and antioxidant vitamins may be related to cognitive function in the elderly. Despite these findings, results from randomised controlled trials into the effects of individual vitamins or multivitamins have not consistently demonstrated cognitive benefits in the elderly using standardised neuropsychological or cognitive assessments. An alternate approach may be to examine brain electrical activity measures such as the steady state visually evoked potential (SSVEP). The current study was a 16 week, double blind, placebo controlled investigation into the effects of daily multivitamin supplementation on cognition and the SSVEP associated with performance of a spatial working memory (SWM) task. It was hypothesised that multivitamin supplementation would improve behavioural measures of cognition and that the SSVEP would be sensitive to the effects of the multivitamin. Participants were 51 elderly women, with subjective memory complaints aged between 64 and 82 years. At baseline, participants completed a range of computerised cognitive tests and the logical memory sub-test from the Weschler Memory Scale. Alternate forms of the cognitive tests were used at post-treatment assessment. The SSVEP was elicited by a 13Hz light flicker during the performance of a SWM delayed response task and a control task. The results revealed that multivitamin supplementation significantly improved memory response time on cognitive measures. At post-treatment, there was a decrease in SSVEP amplitude and increase in latency at right frontal, central and temporal sites during SWM response when compared to baseline. Smaller, less extensive effects were seen in the placebo group. In conclusion the SSVEP may be a useful addition when assessing the potential cognitive enhancing effects of vitamins or other nutraceuticals. A Multi-Component Model of Reconfiguration Processes in Task-Switching: Converging Evidence from ERPs, fMRI and DTI Elise Mansfield,1 Sharna Jamadar,2 Birte Forstmann,3 and Frini Karayanidis,1,4,5 Traditional models of task-switching performance argue that preparation for a switch in task involves an active process which ‘reconfigures’ the cognitive system prior to target onset. Trials on which the same task is repeated are typically treated as the baseline against which this reconfiguration process is measured, as the just-completed task is assumed to remain in a state of readiness, and hence no reconfiguration is required on these trials (Rogers & Monsell, 1995). This reconfiguration process, although widely cited in the literature, is still quite poorly defined, with no clear definition of what it entails. In addition, more recent evidence suggests that some level of preparation is also carried out in anticipation of a repeat in task, suggesting that this condition does not represent the most optimal baseline. The current study attempted to delineate the different levels of preparation which may be carried out in advance of target onset, using a paradigm which manipulated cue informativeness. Fully informative repeat and switch cues as well as partially-informative switch cues were compared against a non-informative cue, which acted as a more neutral baseline condition. This design allowed for the isolation of a number of component processes of anticipatory reconfiguration, including general preparation for an upcoming trial, preparation when participants are cued to switch tasks, and preparation when participants are cued to a particular task. Relationships between behavioural, event-related potential (ERP), functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) indices of preparation were examined to provide a more holistic model of the components of reconfiguration, which included both timing and neural sources of these processes. Modulation of Startle Reflexes by Affect in Adults With Asperger’s Danielle Mathersul, Skye McDonald and Jacqueline A. Rushby Despite severe impairments in affective processing, only one study to date (Wilbarger et al., 2009) has investigated affective modulation of startle in individuals with Asperger’s. This study builds on past research by including concurrent measures of skin conductance (SCR) and heart rate (HR). Fourteen adults with Asperger’s (11 males, mean age 42.86) were matched to 14 controls. Stimuli were IAPS images (6x18 blocks; positive, negative, neutral). Acoustic startle (50ms, 95dB burst white noise) occurred 3s post-onset. Startle responses were measured by peak eyeblink amplitude (electromyogram (EMG) from the orbicularis oculi muscle), maximum change in SCR, and maximum acceleration and deceleration in HR. While both groups had larger EMG to negative than positive images (p=.028), individuals with Asperger’s had a trend towards larger overall EMG responses (p=.065). SCRs in controls differentiated by valence (p=.016) but not in Asperger’s (p=.429). There were no significant differences in HR, either by group or valence. These preliminary results suggest a pattern of atypical startle modulation in adults with Asperger’s. While EMG responses had the typical pattern of modulation by valence, SCRs did not differentiate by valence. This may suggest a failure to orient to positive, socially related stimuli (e.g. Barry Sokolov, 1993; Rushby Barry, 2007; 2009). Does Emotion Equal Emotion? Subjective Report and Objective Physiology Don’t Always Add Up Aimee Mavratzakis, Elaine Molloy and Peter Walla Research on emotion relies on two kinds of data: subjective assessments and objective physiological measurements. Under the latter category a robust finding is that the startle reflex, as measured by eye-blink magnitude, varies systematically with emotional context, increasing in unpleasant contexts and decreasing in pleasant contexts compared to neutral. Traditionally startle response modulation and self-reports are mapped to one dimension of emotion, however little research has examined the extent of coherence among these measures in response to changes in emotion over time. In this experiment startle response modulation (facial electromyography; EMG) was compared with self-reported pleasantness ratings (Self Assessment Manikin; SAM) for novel pleasant, unpleasant and neutral pictures during two counterbalanced conditions of picture viewing: Random presentation (Mix) and hedonic grouping (Block). Arousal indices were also measured from self-report, skin conductance, heart rate, temperature and respiration. The predicted pattern of discrimination between pleasant and unpleasant pictures was observed for self-reported and startle response measures during both viewing conditions. While self-reported picture pleasantness did not differ across viewing conditions differences in startle response patterns were observed. Blocked picture presentations reduced the overall magnitude of startle responses compared to mixed presentations, suggesting that startle modulation is also influenced by temporal processing factors related to consistently valenced stimuli. The discrepancy between subjective and physiological measures of emotion is interpreted with respect to emerging theories of multiple aspects of emotion processing. While the psychological factors underlying modulation of the startle reflex are still not clear future research should concentrate on factors beyond subjective experiences. Electrophysiological Correlates of Static and Dynamic Facial Emotions Angela K Mayes, Andrew Pipingas, Patrick Johnston and Richard Silberstein Facial emotions are important complex social cues in every day life. It is well established that the N170 ERP component elicited over T5/T6 is involved in face recognition and more recently this premise has been extended to include facial emotions. Traditionally, the N170 has been investigated in relation to static images of faces and emotions, however little is known about the neural processes involved in dynamic or moving facial emotions. Steady State Topography (SST) provides a method of assessing continuous changes in neural activity and is therefore an appropriate tool to investigate more naturalistic presentations of dynamic stimuli. The aim of the current study was two-fold; to assess the neural correlates of static and dynamic facial emotion recognition with the use of more traditional ERPs, particularly the N170. Secondly, to investigate the neural correlates of static and dynamic facial emotion recognition with SST. Consistent with previous research, an N170 ERP was found in response to static facial emotions over T5 and T6. A larger N170 was found for dynamic facial emotions over T6 compared to T5. Furthermore, comparing static and dynamic facial emotion processing revealed a significantly larger N170 response for static facial emotions compared to dynamic facial emotions over both T5 and T6. In the same way that ERP research has shown, SST results provided evidence of neural activity to face recognition over temporal regions consistent with the timing of the N170. Furthermore, results also provided evidence of separate neural time courses for dynamic and static displays of facial emotions. Results are discussed in relation to implications of employing the use of complementary electrophysiological methodologies in the investigation of static and moving images of facial emotions. The Effects of Task Difficulty and Music Tempo and Intensity on Visual Selective Attention McCoy, J. Martin, F.H. The aim of this study was to examine the independent and interactive effects of task difficulty and music tempo and intensity on visual selective attention. The presence of music, as an auditory distracter, is thought to increase the mental workload of an individual and so reduce the attentional resources available for a primary task. Eighteen right-handed female non-musicians completed a three stimulus visual task in five auditory conditions (music absent, fast tempo-low intensity, fast tempo-high intensity, slow tempo-low intensity and slow tempo-high intensity) with two task difficulty levels (easy and hard), creating 10 conditions in total. Accuracy and RT in response to correct targets and amplitude and latency of N2, P3b and P3a were also recorded and analysed as stimulus evaluation, resource allocation and orienting of attention to novel non-target stimuli respectively. Contrary to the predicted effects of tempo and intensity on N2 amplitude, the component was significantly decreased under the combination of slow tempo and high intensity. P3a amplitude was found to be significantly larger in the presence of slow tempo than fast tempo music and a similar trend toward significance was observed for P3b amplitude. However, P3b amplitude was significantly smaller in the presence of low intensity music compared to high intensity music. Collectively these results suggest the impact of music as a distraction on early attention processes varies according the tempo and intensity levels of the music, and the difficulty of the primary task. Long-Term Memory Templates Modulate Rapid Plasticity in the Auditory Core Neil McLachlan The recent Object-Attribute Model of auditory perception by McLachlan and Wilson proposed that recognition mechanisms are integral to streaming and the formation of auditory gestalt by priming population codes for auditory features such as pitch. This mechanism may drive the observed rapid plasticity of pitch neurons in the auditory core for changing stimuli and behavioral contexts. Priming the response fields of these neurons allows them to integrate periodicity over relevant spectro-temporal features for a given stimulus type. In a computational model of pitch processing McLachlan proposed that pitch priming is based on the location and pattern of excitation across critical band filters in relation to templates stored in long-term memory for common sound types such as pure tones and harmonic complexes. This paper outlines a neurobiologically detailed computational model of the recognition and pitch priming mechanisms proposed in these earlier models. For concurrent pitches in musical chords the strength of pitch priming was limited by the resolution of critical band filters and would vary dramatically in the presence or absence of templates for these chords. In other words the model predicts that individuals who had not developed a long-term memory template for a specific chord would not be able to segregate its component pitches. This prediction is well supported by behavioral studies. Arousal Changes During Passive Viewing of Emotional Facial Expression AM Murphy, JA Rushby, S McDonald While arousal is generally agreed to be a component of emotion, an accurate measure of physiological arousal produced by emotional stimuli is still a matter of wide debate. The effect of observing positive (happy) and negative (angry) valenced emotional facial expressions on level of arousal were examined using electroencephalogram (EEG) and skin conductance level (SCL). Thirty right-handed female undergraduate students participated in the experiment. Participant’s level of empathy was also measured using the Balanced Emotional Empathy Scale (Mehrabian, 2000). An increase in arousal was reflected by increased SCL and reduced alpha power for the emotional conditions compared to a baseline eyes-closed condition. In addition, an increase in arousal was observed for the angry facial expression compared to the happy. Participants with higher levels of empathy were associated with higher levels of arousal to the positively-valenced (happy) face. This suggests some link between empathy and a heightened responsivity to pleasant emotional facial expressions. Differential measures of alpha power between empathy groups provide further evidence of a link between empathy and physiological arousal. Effects of Bacopa Monniera on Middle Aged Participants: an fMRI Study Chris Neale, Andrew Scholey, Con Stough, Andrew Pipingas and Patrick Johnston. Bacopa monniera (BM) is an Indian herb used for centuries as memory tonic in Ayurvedic medicine. Preclinical research has shown that BM acts as an antioxidant1, improves memory2 and reduces amyloid plaque deposition in animal models of Alzheimer’s disease3. Human studies suggest that BM has a fairly robust benefit to performance on certain attention, working memory and learning tasks4,5,6,7. This study aims to look at the effects of a standardized BM extract (CDRI08) on the BOLD signal, as measured by fMRI, for two tasks which have previously been shown to be sensitive to BM - Rapid Visual Information Processing (RVIP) and Inspection Time (IT). The study employs a double-blind, placebo-controlled, crossover design with treatment periods lasting 90 days with a 120 day washout period. This presentation will outline the methodology employed for this novel 90-day intervention trial. Data from baseline recordings describing the effects of RVIP and IT on fMRI will be presented and analysis discussed. Using Ketamine to Model Semantic Deficits in Schizophrenia Erica Neill The acute administration of the N-methyl-D-aspartate receptor antagonist ketamine induces schizophrenia-like symptoms in healthy individuals. Semantic deficits are a core cognitive abnormality in schizophrenia. In the current study healthy volunteers were administered ketamine whilst performing semantic processing tasks. These tasks included word pairs of differing degrees of semantic relatedness. Semantic processing is a multidimensional construct and two dimensions were investigated: 1) explicit versus implicit processing, that is, whether the semantic relationships in the tasks were processed unconsciously or consciously (using strategic processing); and 2) direct versus indirect, that is whether the words pairs were closely or distantly related. The acute effects of 0.8mg /kg/hr (over 80 minutes) of ketamine were examined in a placebo-controlled double-blind independent group design with 19 participants. It was predicted that ketamine would most significantly negatively impact on the performance of the indirect pairs as has been shown in schizophrenia; and that implicit and explicit processing would be affected. Ketamine administration did result in abnormal performance in response to indirect pairs under implicit presentation, and reduced accuracy but no reaction time differences for explicit pairs. Performance on the direct word pairs tasks (implicit and explicit) were similar across ketamine and placebo conditions, except for the suggestion of abnormal semantic matching in the accuracy data of the direct pairs in the implicit task. These changes mirror the typical pattern of deficits reported in schizophrenia. Future research comparing a schizophrenia and ketamine group directly is needed to determine the similarity of impairments. Elucidating the Mechanisms of tDCS on Sensory Gating Norris SM,1 Degabriele R,2 Lagopoulos J, 1 In humans, transcranial direct current stimulation (tDCS) modulates cortical excitability and studies have reported tDCS to be an emerging clinical treatment option. However, tDCS mechanisms remain unclear. The aim of the present study was to further our understanding of the impact of tDCS on early brain processing. An auditory paired-click paradigm (60 click-pairs: frequency=1000Hz, duration=1ms, ISI=500ms) was used to evoke P50 and N100 ERP components; indices of early sensory processing. Twenty-six healthy subjects were randomized to either an active or sham condition and completed the paradigm pre- and post-tDCS. Both active (n=18) and sham (n=6) tDCS was administered for 20 minutes and ERPs were recorded from nine electrode sites. A significant difference in P50 suppression was demonstrated between groups [F(1,22)=8.075, (p=0.009)]. Suppression increased in the active group post-tDCS [pre:(M=1.896 SD=1.149); post:(M=2.693 SD=1.489)] but decreased after sham [pre:(M=2.748 SD=1.320); post:(M=1.587 SD=1.679)]. Interactions between P50 amplitude and each stimulus were then explored (S1, S2). The variances of the S1 responses across the experiment (i.e. pre- versus post-tDCS) differed between active (mean response increased) and sham (mean response decreased) groups. The variances of S2 responses across the experiment also differed between groups but in the opposite direction (active: mean response decreased; sham: mean response increased). No differences were observed in P50 latency nor N100 suppression or latency. The present study provides evidence that (anodal) tDCS enhances sensory gating in healthy controls. Sensory gating deficits are a core feature in some psychiatric disorders, thus these results suggest that tDCS may have therapeutic potential. Improvement of Inhibitory Control Over Reward-Related Stimuli and Increases in Control-Related BOLD Activity Associated with Monetary Punishment David O’Connor, Rob Hester and Sarah Rossiter Previous research has indentified the neural mechanisms associated with inhibitory control, including the right inferior frontal (rIFC) and anterior cingulate cortices (ACC), but it remains unclear how these mechanisms are influenced by reward and punishment. Understanding this relationship is critical to understanding the failure to control impulsiveness for reward seen in clinical conditions such as drug addiction. Cognitive control was examined using a GO-NOGO response inhibition task in which 15 participants were required to withhold responses to monetarily rewarding stimuli in the presence or absence of punishment for failures to inhibit. Response inhibition accuracy for rewarding stimuli was significantly higher in the punishment condition when compared to the non-punishment condition. Similarly, activation in the rIFC during successful inhibition was found to be greater for the punishment condition. Such a finding implies that inhibition of responses over punishing stimuli may require a more effortful level of cognitive control. Results suggest a particular sensitivity of the rIFC within the cognitive control network to exert top-down attentional control of prepotent responses during circumstances in which an incorrect response can result in a negative outcome. American Ginseng (Panax quinquefolius) Improves Neurocognitive Function in Healthy Young Adults: a Randomized, Double-Blind, Placebo-Controlled, Crossover Study Anastasia Ossoukhova, Prof A Scholey, Dr A Pipingas and Dr L Owen Previous controlled studies demonstrated that Panax (Asian) ginseng lowers blood glucose, improves cognitive function alleviating mental fatigue associated with intense cognitive processing. American ginseng (AG) shares Panax’s glycaemic properties however no previous studies have been conducted evaluating its capacity to modulate cognition. This randomized, double-blind, placebo-controlled, cross-over trial (N = 32 healthy young adults) evaluated the acute mood, neurocognitive and blood glucose effects of 3 doses (100, 200, 400 mg) of an AG extract (standardized to 10.65% ginsenosides) compared to placebo. On study days (separated by a > 7-day wash-out) participants underwent a baseline assessment of mood, cognition and blood glucose, took the day’s treatment followed by the same assessments 1, 3, 6 hours later. Statistical analysis used a two-way (Treatment x Time) ANOVA followed by pre-planned comparisons of each dose’s effect compared with placebo at each time point. The first clinical trial into neurocognitive effects of AG found significant improvement of working memory (WM) performance: spatial span was improved by all doses at all testing times; other WM tasks were differentially improved by the 200 mg dose (with time- and task-specific benefits associated with other doses). Attention (Choice Reaction Time accuracy) was significantly improved by 100 mg at all times and by 200 and 400 mg after 6 h. The 100 mg dose was associated with significantly enhanced ‘calmness’ at 3 and 6 h. No changes on glucose regulation were observed. These properties should be further studied using different dosing regimens and in populations where cognition is fragile. A Role for Omega-3 Diet Supplementation as a Prophylactic Antidepressant Following Traumatic Brain Damage Michaela Pascoe, Nikki Constantinou, Abbey Mortimer and Melanie Murphy Depression is a leading source of disability worldwide. Many individuals show a non response to conventional antidepressants, while others are affected by unpleasant side effects, such as sleep difficulties and nausea. Fatty acids play a pivotal role in depressive disorders, making nutrition related treatment methods a vital area of research. The present study aimed to assess the behavioral and immune modulating properties of 8 weeks of an omega-3 rich diet in 12 healthy male Wistar rats to determine if Omega-3 fatty acids supplementation resulted in harm to healthy animal brains or adverse behavioral side effects, as can conventional antidepressant, using immunohistochemical analysis of AQP4, IL-1‚ and caspase-3, indicative of inflammation-mediated cell-death, eating and drinking behavior, spatial change recognition, novel object recognition and emergence latency. We found no difference in food and water consumption between basal diet and omega-3 supplemented rats. These results support the use of omega-3 as a potential prophylactic treatment of depression. Statistical MMN: a Tale of Two Distributions Bryan Paton, Joshua Skewes, Ivana Konvalinka and Jakob Hohwy The Mismatch Negativity (MMN) is characterised as a specific ERP response to an odd or deviant stimulus in a train of stimuli. There is still some debate over what the exact mechanism is that best explains the MMN but the most popular theory is one based on a sensory memory mechanism. The key elements of this theory are the memory neurons thought to construct some form of model of the standard stimuli. When an incoming deviant stimulus violates this model, the MMN is elicited. When this kind of model is interpreted in the context of a broader theory of neural function, the Free Energy framework by Karl Friston, the MMN comes to represent a paradigmatic example of prediction error. One consequence of this interpretation is that the MMN should respond to statistical regularities in the environment. We present data from 28 individuals who completed a fully statistical frequency deviant MMN where standards were drawn from one distribution and deviants from another distribution. Thus, the relationship between standard stimuli was determined only by their co-membership in a shared distribution, similarly for deviant stimuli. We discuss the results in the light of the Free Energy framework more broadly and Dynamic Causal Modelling (DCM) specifically. The Impact of Caffeine and Taurine on the P3 and N1 Components of the Event-Related Potential Amy Peacock and Frances Martin Although marketed as the core ingredient in energy drinks, taurine’s proposed status as a stimulant has only been tested in conjunction with caffeine, another energy drink constituent well-documented as facilitating attention and performance. The current study investigated the independent effect of taurine, and its interactive effect with caffeine, on information processing and resource allocation using the event-related potential (ERP) components P3 and N2. Participants (N=19) discriminated imminent driving accident scenes from standard traffic conditions under four different arousal conditions (placebo-placebo, caffeine-placebo, taurine-placebo, and caffeine-taurine). Caffeine and taurine dosages were equivalent to quantities within a standard 250 ml energy drink. The presence of taurine and/or caffeine did not significantly alter reaction time, N2 amplitude and latency, or P3 latency compared to placebo. Availability of attentional resources was enhanced after drug ingestion, as evidenced by significantly higher P3 amplitude at parietal midline and right hemisphere sites, compared to placebo. However, this effect was found solely in the presence of caffeine as opposed to the independent or interactive effect of taurine. The absence of a synergistic relationship between caffeine and taurine, or facilitative effect of taurine, suggests that the basic premises underlying energy drink consumption are questionable. Chronic Effects of Isoflavones on Cognition and Aggression in a Female Population Across the Menstrual Cycle Naomi Perry, Andrew Scholey and Patrick Johnston Isoflavones have been shown to have neuroprotective effects in animals1, 2 as well as improving memory3, 4. Findings from human trials are complex, with authors reporting improvements for both sexes in some cognitive domains, but improvements for females only in tasks measuring letter fluency and planning5, 6. Islam et al7 found improvements in working and verbal memory during the menses phase of the menstrual cycle following a 3-day isoflavone rich diet, however the effects of isoflavones have not been studied during other phases. Sixty females not using hormonal contraception will be randomly assigned to take either a 200mg isoflavone supplement or placebo for 2 menstrual cycles. A further 30 females using oral contraception will be included as a positive control (and will receive placebo only). There will be a run-in phase of 1 menstrual cycle for all participants to determine baseline scores. Participants will attend sessions at the BSI 4 times during each menstrual cycle (once per cycle phase) where they will complete measures of mood, a computerized cognitive assessment battery and an emotional Stroop task as a measure of aggression. In addition they will complete a daily symptom report at home. Fifteen participants from each group will complete EEG tasks in the follicular and late luteal phases of the run-in cycle and the second treatment cycle. The tasks will be a go/no-go task and an emotional face recognition task. Improvement in Mental Rotation Tasks- ERP Evidence for Different Strategies Alexander Provost,1 Blake Johnson,2 Scott Brown,1 Frini Karayanidis,1 and Andrew Heathcote,1 We examined whether learning in mental rotation (MR) is due to faster mental rotation speeds (an increase in algorithmic processing efficiency) or a change to a different cognitive strategy in two studies collecting reaction time (RT) and event-related brain (ERP) responses. We predicted that a switch in strategy to automaticity would result in the elimination of event-related potentials (ERPs) related to MR. In contrast, an improvement in algorithmic processing would result in enhanced MR related ERPs. In both studies Pre and Post MEG/EEG session were run bracketing 4 practice sessions. Study 1 used only 10 different stimuli, encouraging the development of stimulus specific automaticity via direct response retrieval. Study 2 used 320 different stimuli, so item specific strategies were discouraged. In both studies RT increased with angular displacement from the upright position in the Pre session, a behavioural signature of mental rotation. P300 amplitudes were also modulated by angular displacement, a neurophysiological signature of mental rotation. Following practice in Study 1 RT did not vary with angular displacement, and MR related ERPs were no longer present. In Study 2 RT continued to increase with angular displacement in the Post session, as did the MR related ERP components. However, these components occurred much earlier than in the Pre and clearly showed an increased modulation of the P300 as a function of angular displacement. The combined evidence suggests two task dependent strategies exist for improvement in MR tasks, which has implications for skill training in a number of applied fields. Lateralised Emotional Processing: Does the Stimulus Presented and Gender of the Participant Influence the Direction of Laterality? Dr Kathrine A Roberts According to the valence hypothesis, the left and right hemispheres are differentially involved in processing positive and negative emotions, respectively. Support for this hypothesis has come from two studies (Jansari, Tranel, & Adolphs, 2000; Rodway, Wright, & Hardie, 2003) that both used a free-viewing discrimination task using facial expressions of a single individual. The overall purpose of the current research was to examine the extent to which this effect generalised to different stimuli from the same stimulus set (Ekman and Friesen, 1976). The results from Exp. 1 directly replicated the effects reported previously (Rodway, et al., 2003) , whereby female participants, in response to the face of a single individual from the stimulus set, demonstrated laterality effects in the direction of laterality predicted by the valence hypothesis. The results from Exp. 2 also only provided partial support for the valence hypothesis, whereby laterality effects only occurred for the positive facial expressions. Exp. 3 was conducted in order to determine whether the results from Exp. 1 could be explained in terms of a perceptual artefact of the stimulus that was presented. The results from Exp. 3 seem to suggest that participants were basing their judgements more on perceptually-driven rather than on emotionally-driven strategies. The results from these three studies indicate that this free-viewing discrimination task is sensitive to stimulus-specific processing strategies, and suggest that future studies need to take the effect of the stimulus presented into account. Long Interval Cortical Inhibition Measured in Humans Using Concurrent TMS-EEG Nigel C. Rogasch and Paul B. Fitzgerald Transcranial magnetic stimulation (TMS) can been used to estimate cortical inhibition in conscious humans using paired-pulse paradigms. For instance, a supratheshold conditioning TMS pulse inhibits the response to TMS at interstimulus intervals between 50 – 250 ms. Such inhibition is termed long-interval cortical inhibition (LICI) and is thought to reflect GABAB- mediated cortical inhibition. Recently TMS has been combined with electroencephalography (EEG) to directly measure LICI from the cortex instead of inferring inhibition via motor-evoked responses in muscles. By using TMS-EEG, LICI can be measured from any cortical area such as motor, prefrontal and parietal cortices. However, little is known about how TMS-EEG measured LICI is affected by altered stimulation parameters. Therefore, the aim of this study was to evaluate the effect of altering conditioning and test intensities on LICI measured with TMS-EEG. Cortically-evoked potentials (CEPs) were measured from the scalp using EEG and motor-evoked potentials (MEPs) were measured from a target muscle using electromyography in healthy volunteers while single and paired-pulse TMS was given over motor or prefrontal cortex. In block 1, conditioning intensities were altered (100%, 120%, 140% of resting motor threshold; RMT) while test intensities remained constant and in block 2, conditioning intensities remained constant while test intensities were altered (110%, 125%, 140% RMT). LICI measured from CEPs over motor cortex were compared between different conditioning and test intensities and between LICI measured from MEPs in the target muscle and LICI measured from CEPs in the prefrontal cortex. Experimental results and interpretations are to be discussed. Cognitive Neuropsychiatry: The History Susan L Rossell Cognitive Neuropsychiatry involves the integration of theories and methods from the fields of clinical psychology, psychiatry, behavioural neurology, cognitive neuropsychology and cognitive science. It aims to understand mental illness and psychopathology in terms of models of normal psychological function. It can also help in our understanding of normal psychological processes by examining the effects of impairment. It is a relatively new discipline and only started in earnest in the 1990s but has been influential, not least because of its early successes in explaining some previously mysterious psychiatric disorders, most notably the Capgras delusion. Symptom based research has been common in the field. In such studies the symptom (paranoid ideas, hearing a voice, the disjointed utterances, the lack of feeling for others, etc.) is examined as if were a neuropsychological abnormality (an aphasia, an agnosia, a personality change, etc.). Data on auditory hallucinations will be presented as an example. An alternative approach is to use cognitive models for a range of normal psychological functions and treat psychiatric phenomena as abnormalities of these functions. Data on semantic memory will be presented as an example. Throughout the rest of this symposium you will be presented with studies that have used cognitive neuropsychiatric techniques to investigate a range of different psychiatric conditions including autism, depression, addiction and schizophrenia. You will also gain insight into the many tools available to researchers in the field including neurocognitive testing, cognitive models, TMS, EEG, fMRI and pharmacological modelling. Visuomotor Integration Deficits Precede Clinical Onset in Huntington’s Disease Miranda J. Say,1,2 Rebecca Jones,3 Rachael I. Scahill,1 Eve M Dumas,4, Allison Coleman,5 Rachelle C. Dar Santos,5 Damian Justo,6 Colin J. Campbell,7 Sarah Queller,8 Arthur Shores,2 Sarah J. Tabrizi,1 Julie C. Stout,7* and the TRACK-HD Investigators Visuomotor integration deficits are evident in Huntington disease (HD), with disproportionately more impairment when direct visual feedback is unavailable. Visuomotor integration under direct and indirect visual feedback conditions has not been investigated in premanifest-HD. Given evidence of posterior cortical atrophy in premanifest-HD, we predicted visuomotor integration would be adversely affected, with greater impairment during indirect visual feedback. 239 CAG-expansion subjects (119 premanifest-HD and 120 early-HD), and 122 controls, completed a Circle-tracing task which included direct and indirect visual feedback conditions. Measures included accuracy, speed, and speed of error detection and correction. Using 3T magnetic resonance imaging brain images, we generated grey and white matter volumes with voxel-based morphometry, and analyzed correlations with circle-tracing performance. Compared with controls, early-HD was associated with lower accuracy and slower performance in both conditions. Premanifest-HD was associated with lower accuracy in both conditions and fewer rotations in the direct condition. Comparing indirect with direct, HD gene expansion-carriers exhibited a disproportionate increase in errors relative to controls, i.e. carriers took longer to detect and correct errors, especially in indirect condition. Slower performance in indirect condition was associated with lower grey matter volumes in left somatosensory cortex. Visuomotor integration deficits are evident many years before the clinical onset of HD, with deficits in speed, accuracy, and speed of error detection and correction. The visuomotor transformation demands of the indirect condition result in a disproportionate decrease in accuracy in the HD groups. Slower performance under indirect visual feedback was associated with atrophy of left-hemisphere somatosensory cortex, which may reflect the proprioceptive demands of the task. Pro-Cholinergic Herbal Extracts and Cognitive Enhancement Andrew Scholey Both intact cognition and cognitive decline involve multiple processes interacting in complex, and possibly idiosyncratic ways. It is therefore unsurprising that monopharmacological treatments for cognitive decline and dementia have had little impact on the disorders. It may be that by affecting multiple systems, nutraceuticals and herbal medicines - ‘nutra’ - may offer a more promising approach. Unlike more mainstream pharmacological agents, nutra agents may contain dozens of active components. It appears that certain plants have evolved with a combination of properties which, in concert, may affect multiple neuronal, metabolic and hormonal systems. Since behavioural processes are themselves modulated by such systems, the effects of herbal extracts may particularly depend upon complex interactions within and between physiological systems. This field offers unique challenges to psychopharmacology. Nevertheless, over the past two decade there has been an rapid growth in research into the human behavioural effects of nutritional interventions and herbal extracts. This paper will briefly draw on specific examples from a systematic assessment of the behavioural effects of nutra interventions concentrating on species of Salvia (Sage) and Melissa officinalis (Lemonbalm), both of which have cholinergic properties, and other relevant to dementia. This work is in its infancy but may uncover treatments with the potential to maintain neurocognitive health throughout the lifespan and to treat conditions where mental function becomes fragile - including dementias. Electrophysiological Correlates of Interference from Emotive Stimuli During Cognitive Processing in Major Depression Rebecca A Segrave,1 Nick R Cooper,2 Richard H Thomson,1 Rodeny J Croft,3 Dianne M Sheppard,4 and Paul B Fitzgerald,1 Individuals with Major Depressive Disorder (MDD) tend to be more susceptible to distraction from negative emotional material than their non-depressed counterparts. This extends to an enhanced vulnerability to interference from mood-congruent stimuli during cognitive processing. We investigated the electrophysiological correlates of competing cognitive and emotional processing demands in MDD. Event-related alpha activity within three individualised alpha subbands was examined during the online information retention phase of a non-emotive WM task with extraneous emotional stimuli (positive, negative and neutral) presented as background images. EEG activity over posterior-parietal cortex was compared between 15 acutely depressed and 16 never depressed right-handed women. Results demonstrated a valence specific dissociation in lower alpha 1 alpha activity between the groups, consistent with greater attentional resource allocation to positive distracters in control participants and to negative distracters in MDD participants. Importantly, no group differences were seen when neutral distracters were displayed. These results demonstrate that activity within the lower alpha 1 band is sensitive to competing emotional and cognitive processing demands and highlight the importance of posterior parietal regions in depression-related susceptibility to affective distractibility during cognitive processing. The Effect of Baseline Essential Fatty Acid Status on Cardiovascular Function and Cognitive Performance L. Sellick, A. Pipingas, D. Crewther, I. Bauer, R. Cockrell, and R. Rowsell A balanced diet is an important part of health, as it is an important part of many bodily systems. Essential fatty acids are part of a balanced diet, as they cannot be manufactured naturally by the body and must be obtained from dietary sources. This study investigated the relationship between baseline essential fatty acid status and its relationship with the cardiovascular system and cognitive performance in a young adult population. It was predicted that healthy essential fatty acid levels would be associated with better cognitive and cardiovascular performance. A computerised cognitive test battery was used to measure cognitive performance; transcranial Doppler ultrasound to measure cerebral blood flow; SphygmoCor pulse wave analysis to measure essential fatty acid levels; and blood tests were used to measure essential fatty acid levels in the blood. Baseline essential fatty acid status significantly correlated with aspects of both cognitive function and cardiovascular health. More specifically, total N6 was found to be the essential fatty acid measure that was significantly correlated with the most cognitive measures, while spatial working memory had the most correlations with essential fatty acid levels. Blood flow through the common carotid artery significantly correlated with multiple essential fatty acid blood measures. Initial results suggest a link between essential fatty acid status and cardiovascular and cognitive performance, indicating a diet containing adequate levels of essential fatty acids may lead to improved cardiovascular and cognitive function. Further research with a larger, broader population is needed to generalise results. Creativity and Brain Functional Connectivity Richard B Silberstein and David Camfield There is an increasing research interest in the neural basis of human creativity. In this study, we investigate the relationship between brain functional connectivity during an attention task and the Creativity Index (CI), a measure of human creativity derived from the Abbreviated Torrance test for Adults. Thirty five (35) female subjects (mean age 20.4, SD 4) and 25 males (mean age 22.3, SD 7) performed the AX version of the Continuous Performance Task (AX-CPT) and a matched reference task. While performing the task, the steady state visually evoked potential (SSVEP) was elicited by a spatially uniform 13Hz visual flicker superimposed over the visual field and the SSVEP event-related partial coherence, an index of brain functional connectivity was calculated for both task for all 2016 unique electrode pairs. This measure was calculated for each point in time in a 5 sec epoch. The relationship between functional connectivity and CI was determined by calculating the correlation coefficient between CI and SSVEP event related partial coherence for each point in time in the epoch. On calculating the correlation between CI and functional connectivity we found that higher CI were associated with increased fronto parietal functional connectivity. This effect, while apparent in the CPT-AX and reference task was stronger in the reference task. These results will also be discussed in the context of the relationship between arousal and creativity. Reliability of Heart Rate Variability Metrics in Epochs of Less Than 8 Minutes R. Slikboer, A. Rossely, G. Kennedy, D. Penman, M. Dubaj, M. Scheir and J. Patterson Heart rate variability measures are used in clinical and research settings, and are divided into two categories, time domain and frequency domain. The standard of 5 minutes of electrocardiogram recording was recommended by the American Heart Association on theoretical grounds. However, apart from the ability to compare studies, practical reasons for the 5 minute standard remain unclear. The study aimed to investigate the minimum length of time required to reliably measure heart rate variability in healthy adults. ECG recordings of 8 minutes from 13 males and 7 females were recorded. The data was averaged and plotted on a graph extending over the eight minutes; this was done for 5 metrics which had previously shown good reliability. All five metrics (SDNN, RMSSD, NN50, HF and LF) showed good reliability from the first minute of recording. In conclusion, the results of this study were not consistent with the 5 minute recommendation of the AHA. This study found that the five metrics can be reliably estimated after just one minute of ECG recording in a sample that is non-ambulatory, relaxed and both physically and psychologically healthy. Do the N2 and P3 Reflect Stimulus — or Response-Related Conflict? Janette L Smith Several studies have linked increases in the N2 and P3 components to response conflict, evoked when multiple incompatible responses are simultaneously activated. However, these studies confound a change of response with a change of stimulus. In this cued-Go/NoGo task, participants were exposed to several types of response-related conflict trials, being required to inhibit a planned response (NoGo target after Go cue), change a planned response to a different one (invalid cueing), and activate an unexpected response (Go target after NoGo cue). On stimulus-related conflict trials, stimuli were a mismatch for the expected target, but demanded the expected response. Strong response-related costs in RT were observed, but RT was not substantially increased for stimulus mismatch trials when these were clearly linked to the required response. For the P3 component, stimulus-related differences were small but significant, in addition to robust response-related increases in positivity when participants cancelled the planned response. However, for N2, the results were less clear, with stimulus- and response-related effects differing for Go and NoGo trials. The results support an inhibitory interpretation of the NoGo P3, and suggest further consideration of the response conflict interpretation of N2 may be required. The Contribution of Luminance, Contrast and Ocular Dominance in Onset Rivalry Jody Stanley, Olivia Carter and Jason Forte When an observer is presented with dissimilar images to the right and left eye, conscious awareness of each image will alternate every few seconds in a phenomenon known as binocular rivalry. In sustained viewing, the timing of these switches appears to be unpredictable, but recent research has suggested that the first conscious experience, or the ‘onset’ period of rivalry, is not random and may be different in its neural mechanism. Differences in luminance and contrast have a significant influence on average dominance during sustained rivalry, and perception of luminance can vary between individuals and across the visual field. We therefore investigated whether contrast also plays a role in onset rivalry. Observers viewed equiluminant rival targets for brief presentations in eight locations of the near periphery and reported the colour that was first perceived in each location. Results show that minimizing differences between luminance and contrast yields a stronger pattern of onset dominance bias and reveals evidence of monocular dominance. These findings are hard to reconcile with current models of sustained rivalry and suggest that different mechanisms may be responsible for determining the initial period of perceptual dominance. An Investigation into the Mechanism of Electrodermal Dishabituation Genevieve Z. Steiner and Robert J. Barry Elicitation and habituation of the orienting reflex (OR) was investigated in the context of indifferent and significant stimuli, focusing on the role of state measures as determinants of the phasic response profile, with the aim to clarify the mechanism driving dishabituation. To examine this, 24 young adult participants were presented with an auditory dishabituation paradigm while electrodermal activity was recorded. Participants completed an indifferent condition in which there was no task in relation to the stimuli, and a significant condition where instruction was given to count the stimuli silently; the order of these conditions was counterbalanced between participants. As predicted, both skin conductance responses (SCRs) and skin conductance levels (SCLs) were found to be larger for the significant compared to the indifferent condition. There was a significant decrease in both SCR and SCL over the first 10 stimuli for both conditions. Phasic response recovery was apparent to the deviant stimulus, and this effect was greater for the significant condition. Dishabituation was apparent in SCRs to the standard stimulus following the deviant stimulus, and this was enhanced for the significant condition. Sensitisation was apparent in SCL following the initial and deviant stimuli. The initial and post-deviant phasic ORs were dependent on pre-stimulus arousal level, however, dishabituation was not directly dependent on deviant-related sensitisation. These findings suggest that dishabituation is not a process of sensitisation, but rather, a disruption of the habituation process. Electrodermal Activity, Pupillometrics, and the Late Positive Complex as Indices of the Phasic Orienting Reflex Genevieve Z. Steiner and Robert J. Barry The Orienting Reflex (OR) performs a fundamental role in attention, stimulus perception, and learning by providing a foundation for an organism to adjust to environmental changes. This study examined electrodermal activity, pupillometrics, and the Late Positive Complex as correlates of the phasic OR. A typical OR-eliciting auditory dishabituation paradigm was employed, while electrodermal data, pupillary dilation responses, and electroencephalographic activity were recorded from twenty-four participants. This procedure facilitated the quantification of response decrement, response recovery, and dishabituation. The OR was operationalised in terms of the stimulus-response patterns described in Preliminary Process Theory. The findings confirmed expectations that electrodermal activity and the Late Positive Complex are indices of the phasic OR. Pupillary dilation response demonstrated an unexpected sensitivity to stimulus novelty only, while the pre-stimulus measure of tonic pupil diameter showed both the novelty and significance effects that were expected of the phasic measure. The unanticipated results concerning pupillary activity provide impetus for further research with a variety of paradigm manipulations. Together, these findings contribute to our understanding of the OR, and support the use of a structured theoretical framework, such as that of PPT, to derive testable predictions in relation to OR-relevant physiological response patterns. Priming Effects Differ Between Word Pairs Related Categorically and Associatively E. J. Tan, S. L. Rossell and G. W. Yelland There is a high degree of variability in semantic priming effects across current research. Many factors have been held to account for this; including type of task used and timing within the tasks. This study investigated if semantic priming effects vary according to type of meaning relationship between word pairs in a healthy population. The lexical decision priming task used word pairs that varied across three types of meaning relationships: semantic (categorical; e.g. almond-peanut), associative (e.g. teeth-dentist) and semantic-associative (e.g. love-hate). The task also manipulated stimulus onset asynchrony and relatedness proportion. 27 undergraduates with no previous history of mental illness or psychiatric medication use completed the task and the National Adult Reading Test (NART), an intelligence measure. Small but significant differences were observed between the priming effects on the three word conditions. Greater priming effects were found for semantic-associative pairs versus purely semantic and associative pairs. These findings thus support the proposition that information is encoded and stored differentially in semantic memory with differing link strength between individual items. Additionally, there appears to be no true effect of an ‘associative boost’ for priming. Despite the small effects in this study, these findings in a non-clinical setting do highlight an important factor and implications that need to be considered in the design of future priming tasks. Reward Sensitivity in Drug Users: How Do Self-Report Measures Relate to a Measure of Reward Sensitivity Derived from Behaviour? Siyun Tan, Daniel Upton, James Gooden and Julie Stout Laboratory decision-making tasks are increasingly being used to investigate risk-taking behaviour, particularly in groups that engage in high risk activities such as illicit substance users. One advantage of this approach is that cognitive and psychological processes that contribute to risk-taking can be identified using a range of techniques that are not easily applied outside of the laboratory. In this study, we used cognitive modeling of behaviour on the Balloon Analogue Risk Task (BART) to isolate and quantify reward sensitivity, an individual characteristic heavily implicated in risk-taking and substance use. Our aim was to determine how this measure of reward sensitivity (derived from behaviour) relates to other measures of reward sensitivity derived from questionnaires that rely on self-report. We correlated these measures of reward sensitivity in a group of heavy substance users (n = 35), light substance users (n = 29) and healthy non-users (n = 28). Self-report measures of reward sensitivity were only weakly associated with reward sensitivity on the BART, and the association was not moderated by substance use. Furthermore, self-reported reward sensitivity had more associations with real-world risk-taking behaviour than BART reward sensitivity. This preliminary evidence suggests that reward sensitivity from self-report and reward sensitivity on the BART assess distinct, largely non-overlapping constructs. Modulation of Blood Oxygenation by Transcranial Magnetic Stimulation Richard H. Thomson,1 Nigel C. Rogasch,1 Jerome J. Maller,1 Zafiris J. Daskalakis,2 and Paul B. Fitzgerald,1 Repetitive transcranial magnetic stimulation is increasingly being investigated in clinical settings for the treatment of psychiatric and neurological disorders such as major depressive disorder, schizophrenia, and dystonia. Using near infra-red spectroscopy (NIRS), very short trains of repetitive transcranial magnetic stimulation (rTMS) have previously been shown to modulate cortical blood oxygenation. In order to investigate the effect of longer, clinically relevant trains of 1Hz rTMS on oxy-hemoglobin (HbO) at prefrontal cortex, the current study applied ten minute trains of rTMS at two different intensities. A similar profile of oxygenation change was observed during the beginning 30-40 seconds of the trains, however for the remainder, subthreshold rTMS returned to baseline while the suprathreshold TMS resulted in a long period of reduced oxygenation. This study has implications for understanding the mechanism involved in efficacious clinical application of rTMS. Laboratory Measures of ‘Risky’ Decision Making in Substance Users: What Can Cognitive Models Tell Us That Behaviour Can’t? Daniel Upton Substance use behaviour results from a complex interaction between life experience and biology. Cognitive psychologists take the view that from this interaction emerges a cognitive and psychological profile that drives substance use and other high-risk behaviours. Our approach is to study the cognitive and psychological processes underlying high-risk behaviour using laboratory decision-making tasks and cognitive models of these tasks. The Iowa Gambling Task (IGT) has been used by our group and others to study risk-taking behaviour in substance users. From this work, it appears that groups with substance use problems fail to modify their behaviour following punishment and therefore continue to make disadvantageous decisions. However, results from other risk-taking tasks suggest that healthy individuals display similar behaviour under the right conditions. I will present results from our recent work on decision making in a group of heroin users (n = 27) and age, gender, and IQ matched healthy non-users (n = 26). Our data suggest that risk-taking behaviour differs between heroin users and healthy non-users only under certain conditions, but measures of reward sensitivity, decision consistency and memory (derived from cognitive models of these tasks) reliably differ between groups across tasks. A Role for Affectivity in Rapid Facial Mimicry: an Electromyographic Study Kandice J. Varcin, Julie D. Henry, Jenny L. Richmond, & Phoebe E. Bailey Emotional facial expressions evoke rapid, spontaneous and covert facial reactions in the perceiver that are consistent with the emotional valence of the observed expression. This facial mimicry response has been associated with various social cognitive processes such as facial affect recognition, theory of mind, and the broader construct of empathy. The present study aimed to investigate the underlying mechanisms of rapid facial mimicry to determine if this reaction is a purely motor matching response or whether this response represents underlying affective processes. The corrugator supercilii (brow) and zygomaticus major (cheek) muscle activity of non-clinical undergraduate participants (n = 60) was quantified (1000 ms post-stimulus onset) using facial electromyography (EMG) while participants viewed images of (i) happy and angry facial expressions, (ii) inverted happy and angry facial expressions, and (iii) sad and happy eyes, and sad and happy mouth expressions. Across all conditions, participants displayed a distinct pattern of EMG responding consistent with the affective valence of the emotional expression, as opposed to merely matching the observed stimuli. That is, results demonstrated greater zygomaticus activity in response to happy faces (upright and inverted), eyes and mouth relative to angry and sad, and greater corrugator activity to angry faces (upright and inverted) and sad eyes and mouth relative to happy. Results of the present study suggest that rapid facial reactions in response to emotional expressions are not purely motor-mimetic, non-affective reactions. Instead, the current findings provide novel evidence for the contention that affective processes underlie rapid facial mimicry reactions. The Development of an Ecologically Valid Tool for Assessing Stress in the Laboratory: the Multi-Tasking Framework Dr Mark A. Wetherell In order to assess the pathways by which stress leads to deleterious outcomes in terms of health and well-being, it is necessary to observe individuals while they are experiencing stress. This is typically achieved in two ways; i) to assess individuals who are experiencing naturally occurring periods of stress (e.g., through their work or home life) or ii) to observe individuals during a controlled period of stress usually administered in the laboratory. Whilst the former method has high external validity, such methods are often time consuming and lack control. In contrast, laboratory stressors afford more control; however, the techniques employed rarely represent situations that would be experienced in the real world. Laboratory stressors should provide a snapshot of how an individual would respond to real life stress, and as such, there is a need to develop ecologically valid stressors that can be applied in a laboratory setting. The Multi-tasking Framework is a performance-based platform for the presentation of simultaneous tasks and elicits stress through the manipulation of cognitive workload either by increasing the number of tasks a user must attend to or by increasing the individual difficulty of those tasks. As such, the Framework is analogous to a variety of working environments that require a user to attend and respond to several stimuli simultaneously. Data will be presented to demonstrate the effects of the Multi-tasking Framework and differential effects of increasing workload intensity on psychobiological parameters of stress reactivity. Applications of the Framework will also be presented, including results from a recently developed paradigm designed to assess the effects of Multi-tasking stress during periods of critical evaluation. Training Increased Theta Activity on a Functional Brain Source: Pilot Data David White,1 Dr. Marco Congedo,2 Dr. Joseph Ciorciari,1 and Prof. Richard Silberstein,1 This report summarises preliminary data exploring the possibility of training increased theta-band activity in a functional brain source. Recent approaches to real-time training of brain activity, known as neurofeedback, provide spatially specific training protocols using fMRI or by combining source localisation with multi-channel EEG. The present study introduces a method using real-time training of a weighted source of brain electrical activity identified using blind source separation (BSS). First, a functional network localised to parietal and medial-temporal regions showing increased theta power was identified during completion of a spatial navigation task, using group BSS. The extent to which self-regulation of such a brain source is possible was then explored, as well as the effects of any such regulation. Individual neurofeedback weights were determined by correlating individual source activity during completion of the original spatial navigation task, identifying the source demonstrating the strongest correlation with the group source. Participants then completed 20 sessions of a neurofeedback training protocol to increase peak theta activity relative to total theta in this source, with a number of memory and learning tasks assessed pre- and post-training. Preliminary data demonstrate significantly increased peak theta ratio during feedback from pre-feedback baseline, significant learning across training sessions, as well as evidence of self-regulation when assessed on a series of ‘up’ and ‘down’ feedback trials at the conclusion of the training. Preliminary findings of behavioural and electrophysiological changes associated with the training on learning and memory tasks are also reported. Do Age Differences in Task Switching Reflect Difficulties in Preparatory or Target-Driven Processes? L. R. Whitson, D. Vujkovic, P. T. Michie and F. Karayanidis AIMS: Task-switching paradigms are used to examine age-related differences in cognitive control. Participants complete single task and mixed task blocks. RT switch cost [(switch - repeat trials from mixed task blocks)] reflects active task-set reconfiguration processes, essentially measuring how efficiently we are able to switch between two competing task-sets. A previous study has shown that Older adults reduce switch costs over a number of sessions, and are equivalent to Young adults at test. This study examined whether this behavioural difference was reflected in event-related potentials (ERPs). METHODS: 39 participants (20 young, 19 older) completed two sessions of cued task switching. We examined RT switch cost, together with the differential switch positivity for age differences across two sessions. RESULTS: Young adults switch costs reduced with increased preparation during both sessions, however, Older adults showed this reduction in session two only. In cue locked waveforms, differential switch positivities are present for the younger group in both sessions. These ERP differences began later and were greatly attenuated for Older adults. In the stimulus-locked waveforms, differential negativity is larger and more prolonged for Older adults across both sessions. These findings suggest Older adults may be experiencing prolonged processing at stimulus onset, due to less efficient preparatory processes. CONCLUSIONS: When combined these results suggest that Older adults develop efficiency in switching between multiple tasks across two sessions. The results are discussed in the context of theories of cognitive aging and functional significance for Older adults. The Role of Emotion in Moral Judgment Alexis Whitton, Associate Professor Julie Henry, Dr. Jessica Grisham and Associate Professor Peter G. Rendell Whilst most researchers in the field of moral psychology today subscribe to models of moral judgment that incorporate both emotion and reason, the relative contribution of each remains unclear. One particularly influential model, however, is Haidt’s Social Intuitionist Model of moral judgment. Haidt’s model stipulates that affectively laden intuitions drive most, if not all, of our moral behaviour, whilst reasoning is simply employed post hoc to justify this behaviour. Numerous studies have provided support for this theoretical framework, showing that emotions manipulated outside of conscious awareness can influence moral judgments and behaviour. The current research aims to clarify the relationship between disgust sensitivity and severity of moral judgments, and whether this relationship is unique to disgust, or can also be observed in other negative emotions, such as anger. With the Social Intuitionist Model in mind, the current research also attempts to highlight any conflict between ‘intuitive’ (i.e. automatic, affect-driven) responding and self reported moral judgments, using more objective psychophysiological indices of emotion. Undergraduate participants (N=90) were assessed across a range of emotional functioning measures and were then randomly allocated to one of three groups in which either disgust, anger or no emotion was induced in session. Responses to a variety of both written and visual moral violations were then measured using both self-report ratings and facial electromyography. The results further inform our understanding of the conflict between ‘intuitive’ responding and self reported moral judgments, as well as the trait emotional variables that influence moral judgment. |
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