Dense-array ERPs were recorded in response to a set of fear emo-tional facial expression and neutral faces using an incidental taskduring event related potential recording. The paradigm was builtusing frequently presented faces depicting neutral expression, ran-domly mixed with fear emotional facial expression that appearedto a smaller frequency. Underlying brain sources were estimatedusing Bayesian Model Averaging (BMA). The ERPs showed astrong modulation in the amplitude of an early negative compo-nent in the temporal region (N170) and a positive one at frontalsites in the same latency range by emotional facial expression.BMA analysis suggested the existence of a specic emotional neu-ral system involved in the processing of emotional facial expres-sion. This nding stands in contrast to previous modelssuggesting that N170 processes linked to structural analysis offaces precede analysis of emotional expression. In fact, it mayreect early top-down modulation from neural systems involvedin automatic emotional processing.
235. Dysfunctional attentional networks in children with
attention decit hyperactivity disorderT.M. Bravo, M.
Martn, S. Guerra (Cuba)
Recent research in attention has involved three networks ofanatomical areas that carry out the functions of orienting, alertingand executive control (including conict monitoring). Studies ofADHD children using tasks somewhat similar to the AttentionNetwork Test (ANT) have shown some evidence of abnormalitiesin alerting and/or conict. The objective of the present study wasto investigate these three particular aspects of attention in chil-dren with ADHD. Twenty-ve medication-naive boys withADHD and 25 healthy controls, aged 8 to 12 years, were studied.A child-friendly version of the ANT was used to measure the e-ciency of the three networks. Three subtractions where computedto obtain the alerting, orienting and conict score for each partic-ipant. Across all trials, children with ADHD showed signicantlylonger reaction times (RTs) and more errors than healthy con-trols. Children with ADHD had a signicant impairment in theirconict system. Children with ADHD showed a numerically butnot signicantly larger alerting and orienting eect. This studysuggested that the dysfunction in executive control system is thestrongest decits in children with ADHD. These ndings supportthe notion that ADHD patients have a specic attentional decit,rather than a global one.
236.Hot and Cool executive dysfunction in children with
attention decit hyperactivity disorder (ADHD)T.M.
Bravo, M. Martn, M. Domnguez (Cuba)
ADHD is regarded as a construct that subsumes multiplepotentially dissociable but overlapping cognitive proles. Theobjective of the current study was to reconsider the impairmenton executive function (EF) in ADHD on the light of distinctionbetween aective/motivational (hot) and more purely cognitiveaspects (cool) of EF, examining the performance on a neuro-
psychological battery. Twenty-ve children with ADHD and 25healthy controls were administered measures of estimated intellec-tual ability, sustained attention, set shifting, inhibitory control,delay aversion, and decision-making. Behavioural ratings wereobtained. The controls were matched in gender, age and IQ withthe ADHD group. ADHD children performed worse than con-trols in all tasks. A discriminant analysis was conducted, the com-bination of the entire measures discriminated correctly the 88% ofboth groups. There was an overlapping distribution of impair-ment based on percentage of individuals in each groupimpaired (>1.5 SD). Twenty percent of children with ADHDshowed dysfunction only in hot EF, 8% in cool EF, and60% had dysfunction in both. The probability of impairment inhot and cool EF was independent. The presence of impair-ments in incentive, motivational and reward-related processingsuggests that both hot and cool EF decits are present in chil-dren with ADHD.
237. Application of the event related potential contingent
negative variation in the evaluation of the cognitive functions
of patients aected by endogenous depression monopolarT.
Acosta, A. Montoya, C. Acosta (Cuba)
We studied variations in CNV in monopolar endogenousdepression. 18 depressed patients (3066 years) and a controlpaired sample of healthy subjects were evaluated using CNV.The analysis of the morfological type of CNV was sensitive to dif-ferentiate among patients and controls, with a highest prevalenceof slow CNV (Type B) in patients. There was a signicantdecrease of the width of the CNV at Cz. The extent and the aver-age area of the CNV are not dierent in the patients and in thecontrols, which suggests that in the depressed patients dont exista global cortical activation. The CNV showed signicant decreaseof the extent in anterior regions in patients, which might be due tothe sleep disorders associated with depression.
238. Attentional network task (Ant) performance in schizo-
phrenic patients and their unaected rst degree relatives:
Potential endophenotypesS. Guerra Lopez, T.M. Bravo
Collazo, J. Iglesias Fuster, A. Reyes Berazan, M.A. Pedr-
oso Rodrguez, R. Mendoza, M. Domnguez, M. Martn
We studied family association in attentional performanceusing the Posners paradigm (ANT) in 26 schizophrenic patients,30 unaected rst degree relatives and 30 healthy controls. Weexamine the eciency of the segregated executive control, alertingand orienting networks by measuring how response latencies(reaction time) were modied by the cue position and the ankingstimuli. We also explore if these alteration attentionals are presentin unaected family members at a higher rate than in the generalpopulation (family association). The ANOVA reveals main eectsof anker and cue condition and a signicant interaction eectbetween anker and study groups. The schizophrenic patients
Society Proceedings / Clinical Neurophysiology 119 (2008) e99e164 e157