Poster presentations sessions 1, 2, 3

Posters session 1

Auditory P300 is more sensitive than visual P300 to the attentionimpairment in absence epilepsy

C.C. Duncana, A.F. Mirskyb

a Uniformed Services University of the Health Sciences, Laboratory of ClinicalPsychophysiology, Department of Psychiatry, Bethesda, Maryland, USAb National Institute of Mental Health, NIH, Bethesda, Maryland USA

We report the results of an investigation of P300 measures of informationprocessing in two groups of patients with seizure disorders, those withidiopathic generalized epilepsy of the absence type, and those with complexpartial epilepsy. Studies have demonstrated that absence patients performmore poorly than complex partial seizure patients on behavioral tests ofsustained attention (the Continuous Performance Test, or CPT). Duncan (1988)reported that P300 was significantly reduced in a group of absence patients ascompared with healthy controls. The present ERP investigation was under-taken to further illuminate the attention deficit in absence patients, as com-pared to that in complex partial seizure patients, by evaluating measures ofP300 elicited during performance of the CPT.

ERPs were recorded while participants with complex partial seizuredisorder—matched to the absence patients in an earlier study—performedauditory and visual versions of the CPT. A significant reduction in the amplitudeof P300 on the visual CPT was observed in both groups of seizure patients ascompared to controls (absence=complex partialbcontrol). In contrast, P300 onthe auditory CPT was reduced only in the group with absence seizures(absencebcomplex partial=control).

These ERP data support and amplify previous behavioral findings ofthe impaired capacity of absence patients, as compared to complexpartial patients or healthy controls, to mobilize and sustain attentionalresources. Reasons for the greater sensitivity of auditory than visualattention tasks to the pathophysiology of absence epilepsy are unknown.However, our results suggest that two possible factors may be involved:(a) There are separate visual and auditory attention systems within thebrain, and the latter is more vulnerable than the former (Duncan et al.,2005); and (b) There is increased vulnerability of auditory processing,which depends on intact mechanisms in the brainstem, which aredysfunctional in patients with absence seizures (deemed “cortico-reticular epilepsy” by Gloor, 1988). Thus, behavioral measures of attentiondeficits in patients with absence seizures may reflect compromisedauditory processing.

doi:10.1016/j.ijpsycho.2008.05.011

Relating the P3B wave to memory performance in 11-year-old children

O.Bouchera,C.H.Bastiena, S.W. Jacobsonb, J.L. Jacobsonb,D.Saint-Amourc,G.Muckleaa School of Psychology, Universite Laval, Quebec, Canadab Department of Psychiatry and Behavioral Neurosciences, Wayne State UniversitySchool of Medicine, Detroit, USAc Department of Ophthalmology, CHU Sainte-Justine, Montreal, Canada

One of the most influential theoretical interpretations regarding thefunctional significance of the event-related potential (ERP) P3b wave relates tomemory processing. While this interpretation has received previous support, itremains unclear which aspects of memory processing are associated with P3blatency and amplitude. The few studies that have related P3b to performance onepisodic memory tests, assessing processes such as long-term storage andretrieval of information, have produced inconsistent results. Furthermore, thesestudieswere often limited by small sample size and broad age ranges. The aimofthis study is to extend previous reports by examining the relation between P3band performance on working memory and auditory verbal learning tasks in ahomogenous sample of children. In a birth-cohort study of Inuit children, 80children (mean age=11.3 yr; range=10.3–12.3) were successfully assessed onboth an ERP auditory oddball paradigm and a neurobehavioral evaluationcomprised of tasks targeting different aspects of memory functioning: the DigitSpan subtest from theWechsler Intelligence Scales for Children, 4th edition, andthe California Verbal Learning Test for Children (CVLT). Pearson correlationswere calculated relating P3b (latency and amplitude at Cz) to standardizedscores on the Digit Span (Forward and Backward conditions) and CVLT (wordlistfirst immediate recall, long-delay recall and recognition hits). The correlationmatrix revealed a significant association between P3b latency and Digit SpanForward (r=− .40, p≤ .001), which is consistent with reports from previousstudies. This association suggests a relation between information processingspeed and the amount of information that can be retained in short-termmemory. Furthermore, significant relations were observed between P3bamplitude and CVLT long delay recall (r=.24, p≤ .05) and recognition total hits(r=.35, p≤ .001). To our knowledge, this is the first study to report positiveassociations between P3b amplitude and performance on an episodic memorytask. These results suggest that auditory oddball P3b amplitudemay provide anindicator of the child's ability to recruit cognitive resources involved in theencoding and storage of information in episodicmemory.Whether this relationreflects a specific link between this component and memory processing or amore general attention allocation process remains unclear.

doi:10.1016/j.ijpsycho.2008.05.012

Individual differences in cortical processing of affective faces:Heritability and behavioral correlates

A.P. Anokhin, S. GolosheykinWashington University School of Medicine, Department of Psychiatry,St. Louis MO, USA

Facial expression of emotion is a key mechanism of non-verbal socialcommunication in humans. Deficits in processing of facial emotion have beenimplicated in psychiatric disorders characterized by abnormal social behavior,such as autism and schizophrenia. Identification of genetically transmittedvariability in the neural substrates of facial processing can elucidate thepathways by which genetic factors influence social behavior and provideuseful endophenotype for psychiatric genetic research. However, little isknown about genetic versus environmental influences on cortical processing

International Journal of Psychophysiology 69 (2008) 207–241

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of facial emotion. This study examined event-related brain potentials (ERPs)elicited by changes in facial expression in adolescent twins (age 12, 47monozygotic and 42 dizygotic pairs). Faces from Ekman and Friesen's set withhappy, fearful, and neutral expressions were administered in a continuousmode, such that different expressions of the same face instantaneouslyreplaced each other. Emotional expressions always followed a neutral ex-pression. Face identity changed only when a neutral face was displayed. Thisexperimental design allowed us to isolate responses to expression changethat were unconfounded with responses to face onset. Changes of emotionalexpression elicited face-specific N170 wave with a peak in the righttemporoparietal region and a P3 wave over bilateral parietal regions. Geneticanalyses using model fitting approach showed that substantial proportion ofthe observed individual variation in ERP responses can be attributed togenetic factors (up to 36–55% for N170 and 48–74% for P3 components,respectively). Finally, deficit in ERP components elicited by affective facialexpressions significantly correlated with behavioral problems assessed usingChild Behavior Checklist (CBCL): externalizing problems were associated withreduced N170, while social problems were associated with reduced P3component. To our knowledge, this is the first study to demonstrate thatindividual differences in neuroelectric responses elicited by human faces arestrongly influenced by genetic factors.

doi:10.1016/j.ijpsycho.2008.05.013

Loss and error information impact feedback-locked brain potentials in agambling task

L.D. Nelsona, E.M. Bernata, C.B. Holroydb, W.J. Gehringc, C.J. Patricka

a University of Minnesota, Psychology Department, Minneapolis, USAb University of Victoria, Victoria, Canadac University of Michigan, USA

This study examined the extent towhich primary loss–gain and secondaryerror–correct feedback parameters influenced the feedback-related negativity(FRN) and feedback-locked P300 in a gambling task. In this task, participantsselected between twomonetary amounts and then viewed whether they wonor lost the amount that they chose, as well as whether the alternative choicewould have resulted in a win or loss. Thus, in addition to indicating the actualmonetary outcome, the feedback signified whether a choice was better(correct) or worse (error) than the alternative outcome. Gehring andWilloughby (2002) reported that the loss–gain distinction and not theerror–correct distinction affected the FRN in their task. However, subsequentresearch has revealed that the salience of loss–gain or error–correct stimulusparameters is critical to predicting which distinction will show the primaryeffect. Using the Gehring and Willoughby (2002) gambling task on a largersample (N=148), we show that the error–correct parameter is significantlyrelated to FRN amplitude in this task, but to a lesser extent (approximatelyone-sixth the effect size) than loss–gain. Based onpriorwork, we attribute thisdifference between loss–gain and error–correct effects to the fact that the lossversus gain parameter was emphasized more strongly in the task demands.

We also parsed the feedback response using time-frequency analysis intoa theta component reflecting the FRN, and a delta component reflecting theP300. As for the time-domain FRN, theta-FRN was more heavily influencedby the loss–gain factor than the error–correct factor. The error–correctparameter of the feedback, however, showed a stronger relationship tothe delta-P300 such that the effect size of the error–correct and loss–gainparameters were similar in magnitude. Thus, overall, the theta-FRNcomponent was affected more by the loss–gain than error–correct distinc-tions, while the delta-P300 was affected by the two factors equally. Thesefindings suggest that the discrepancy element of feedback made most salientby the task demands (e.g., loss versus gain) primarily affects the theta-FRN,whereas the delta-P300 reflects a later, more evaluative process that isseparable from the discrepancy signaled by the feedback. Finally, we showthat the error–correct main effect is strongest in loss trials for theta and gaintrials in delta, suggesting a further distinction between these two time–frequency components of the feedback response that should be evaluatedfurther in future research.

doi:10.1016/j.ijpsycho.2008.05.014

Source localization of time and time–frequency measures of the ERN

U. Vaidyanathana, E.M. Bernata, S. Aviyenteb, C.J. Patricka

a University of Minnesota, Psychology Department, Minneapolis, USAb Michigan State University, USA

Time–frequency (TF) analyses of event-related potentials (ERP) are usefulin the decomposition of brain-wave activations that overlap temporally andspatially. The error-related negativity (ERN) component has been shown tohave overlap with other activity, and to benefit from TF decomposition.Previous TF analyses have demonstrated that theta oscillations (3–7 Hz) are adominant frequency during the ERN. A recently proposed TF decompositionutilizing PCA (Bernat et al., 2005) has characterized ERN activity similarly (Hallet al., 2007). The current report evaluates source localization of time and TF-PCA measures of both response-ERN (cf. Gehring et al., 1993) and feedback-ERN data (cf. Gehring and Willoughby, 2002). The resulting time and TFcomponents were compared using a single-source equivalent dipole solution,as both response- and feedback-ERNs have been demonstrated to contain aprimary activation of the anterior cingulate cortex (ACC) and are compatiblewith an ACC single-source model. After TF-PCA analysis determined the TF-location of the component, the original time-domain signals were band-passfiltered to obtain response- and feedback-ERN activity that corresponded tothe TF-PCA components. Single-source dipole models were then fit to thesecomponents using BESA software. A range of filters that varied in theta energywere used to compute the response-ERN and feedback-ERN, including theunfiltered time-domain signal. The resulting dipole fits were compared usingboth the location of the dipole and percentage of unexplained residualvariance in the time-domain signal. Results for both the response- andfeedback-ERNs suggested that the best sourcemodelswere obtainedwhen theupper- and lower-bound for filters for the time-domain signals correspondeddirectly to maximal theta energy in the TF components. Additionally,unfiltered time domain components for both the response-ERN and feed-back-ERN proved to have theworstfit out of all the sourcemodels. Findings arediscussed in terms of the benefits of the TF decomposition of ERPs.

doi:10.1016/j.ijpsycho.2008.05.015

Longitudinal relationships between bioavailable testosterone, cortisoland depressive symptoms in men treated for prostate cancer

S. Hervouet, J. Savard, H. IversSchool of Psychology, Universite Laval, Quebec, QC, CanadaLaval University Cancer Research Center, l'Hotel-Dieu de Quebec (CHUQ), Quebec,QC, Canada

Introduction: There is evidence of a relationship between testosteronedepletion and depression in elderly men. In prostate cancer, one commontreatment androgen deprivation therapy (ADT), aims at suppressing malehormones. Depression in this population might therefore be associated withdecreased testosterone levels. A relationship with cortisol levels is alsopossible given the functional relationship observed between testosterone andcortisol levels in depression.

Purpose: (1) To investigate the longitudinal evolution of bioavailabletestosterone, cortisol and depressive symptoms in men with prostate cancertreated by radiation therapy with or without ADT, and (2) To determinewhether changes in levels of bioavailable testosterone and cortisol are linkedto variations in depressive symptoms over time.

Method: A total of 60 men with localized prostate cancer composed thestudy sample, which was divided into two groups: (a) radiation therapy(n=32) and (b) radiation therapy combined with ADT (n=28). Participantswere evaluated before initiating treatment and at repeated intervals for aperiod of 16 months (i.e., at 2, 4, 6, 8, 12 and 16 months), using the StructuredClinical Interview for DSM-IV (SCID), the Structured Interview Guide for theHamilton Depression Rating Scale (SIGH-D), the Hospital Anxiety andDepression Scale (HADS) and the Beck Depression Inventory (BDI). Bloodsamples of bioavailable testosterone and cortisol were also taken at eachassessment in the morning.

Results: Linear regression mixed models revealed no significant timeor group effect on any of the study measures and no significant interaction:SCID: F (6, 255)=0.76, p=.60; SIGH-D: F (6, 254)=1.96, p=.07; HADS-depressionsubscale: F (6, 255)=0.42, p=.86; BDI : F (6, 255)=0.92, p=.48. Changes in

208 Poster presentations sessions 1,2,3 / International Journal of Psychophysiology 69 (2008) 207–241