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P17-6 N400 deficits from semantic matching of pictures in probands and first degree relatives from multiplex schizophrenia families
S204
Posters
psychiatric disorders, including not only psychotic symptoms but also nonpsychotic symptoms.
P17-6 N400 deficits from semantic matching of pictures in probands and first degree relatives from multiplex schizophrenia families
P17-4 Clinical application of the P300 component of event-related potentials
S. Guerra1 , M. Martin1 , M.A. Bobes1 , A. Ibanez1 , M. Valdes Sosa1 Department of Clinical Neurophysiology, Moron General Hospital. Ciego de Avila, Cuba
Y. Takahashi1 , A. Toyomaki1 , T. Koyama1 1 Dept. of Psychiatry, Hokkaido University Graduate School of Medicine, Sapporo, Japan
Objective: Endophenotypes is one emerging strategy in schizophrenia research that is being used to identify the functional importance of genetically transmitted, brain based deficits present in this disease. Currently, event-related potentials (ERPs) are timely used in this search. Several ERPs, including N400, present deficits in relation to schizophrenia. Methods: In order to assess the genetic liability of N400 as a possible endophenotype, a picture semantic-matching task (congruent and incongruent pairs of pictures) was performed by 21 unaffected firstdegree relatives of patients with schizophrenia, 21 DSM-IV diagnosed schizophrenia probands, and 21 control subjects, matched by age, gender and educational level. Probands and relatives were selected form Multiplex schizophrenia families. Results: Significantly reduced N400 amplitude for congruent categories in N400 was found in probands and relatives in relation to controls. The latency onset and the maximum peak latency of N400 were delayed in both, relatives and probands groups compared to control. The voltage maps of incongruous-minus-congruous difference indicate a more reduced right restricted negativity in probands and relatives, when compared to a wide extended bilateral negativity in controls. No general differences were found between patients and relatives. Conclusions: These results demonstrate an electrophysiological deficit in semantic match processing in clinically unaffected first degree relatives of patients with schizophrenia, suggesting a possible use of this marker as endophenotype.
Objective: Abnormality of P300 waveforms of event-related potentials (ERPs) has been suggested to represent an aspect of the pathophysiology of schizophrenia. However, very few attempts have been made at measuring P3b in not 2-tone but 3-tone oddball task. In the present study, we sought to compare P3b component elicited in between 2-tone and 3-tone oddball tasks. Furthermore, we examined EEG frequency characteristics which have been linked to specific cognitive functions such as stimulus encoding and selective attention during an auditory oddball task. We evaluated differences of these P3b and induced EEG frequency changes between schizophrenia patients and normal controls. Methods: EEG data were acquired from patients with schizophrenia (n = 20) and age-matched normal comparison participant (n = 20).EEG was recorded on both 2-tone and 3-tone task. To examine whether schizophrenic patients have abnormalities in frequency-domain, eventrelated alpha attenuation, as well as in time-domain EEG phenomena, such as event-related potential, we compared alpha power change and P300 elicited simultaneously in response to the presentation of target tones in an auditory oddball paradigm between patients with schizophrenia and normal controls. Results: Schizophrenia patients showed significantly reduced P3b amplitude at Pz compared to normal controls. There were tendency of different EEG frequency changes between schizophrenic patients and normal controls. Conclusions: These investigation are useful order to know schizophrenia patients. P17-5 Effects of vocalizing on auditory N1 component of event-related potentials in schizophrenic patients A. Iwanami1 , Y. Okajima1 , N. Kato1 1 Department of Psychiatry, Showa University School of Medicine, Japan Objective: Corollary discharge is a brain electrical activity associated with self-monitoring, which distinguishes self from others in thoughts or behaviors. Corollary discharge can be non-invasively assessed using eventrelated potential (ERP) recordings in humans. Some previous studies have revealed that the amplitude of the N1 component elicited during an “oddball” task is reduced while a healthy subject is vocalizing, which may index the effect of corollary discharge on auditory ERPs. In this study, we attempted to assess the effects of vocalizing on the N1 component during a passive oddball task in 10 healthy adults and 10 schizophrenic patients. Methods: Event-related potentials were recorded during a passive auditory task while subjects were silent, and while subjects were vocalizing. Subjects were presented with a series of 300 auditory stimuli with a fixed interstimulus interval of 1 sec. In the task, 85% of the stimuli were tones of 1 KHz, and the other 15% tones of 2 KHz. The stimulus intensity was 75 dBSPL. According to the international 10 20 system, the scalp electroencephalogram (EEG) was recorded. Vertical and horizontal electrooculograms (EOG) were recorded from electrodes placed below and at the outer canthus of the right eye. EEG samples were acquired every 1 msec from 100 msec before to 900 msec after the stimulus onset. The responses to frequent and rare tones and were averaged separately. N1 was defined as the most negative peak between 60 and 150 ms poststimulus. Amplitudes were measured with respect to an average voltage during the 100 ms prestimulus. Results and Conclusions: The amplitude of N1 component was lower during vocalizing than during the silent baseline condition in normal controls, but not in schizophrenic patients. These results may replicate that the auditory N1 component may reflect the effects of corollary discharge.
1
P17-7 Attentional network task in schizophrenic patients and their unaffected first-degree relatives: a potential endofenotype S. Guerra1 , J. Iglesias2 , M. Martin2 , R. Mendosa2 , M.D.L.A. Pedroso1 , M.A. Bobes2 1 Department of Clinical Neurophysiology, Moron General Hospital. Ciego de Avila, Cuba, 2 Department of Biological Psychiatry, Cuban Neuroscience Center, Havana, Cuba Objective: In this paper, we investigate through a study of family association the attentional performance in 26 schizophrenic patients, 30 unaffected first degree relatives and 30 healthy controls using the ANT. Methods: Our ANT is one combination of a spatial cueing task and a flanker task, it contains three experimental blocks with 60 trials each one and 12 conditions (4 cue levels by 3 target levels). We examine the efficiency of the segregated executive control, alerting and orienting networks by measuring how response latencies (reaction time) were modified by the cue position and the flanking stimuli. We also explore if these alteration attentionals are present in unaffected family members at a higher rate than in the general population (family association). Results: The ANOVA reveals main effects of flanker and cue condition and a significant interaction effect between flanker and study groups. The schizophrenic patients and their relatives had a longer median reaction time than the control group (1026.7; 1001.1 and 845.9 respectively). Finally, the ANT data revealed that the schizophrenic patients and their biological relatives differed significantly from the healthy control in terms of their conflict resolution and the orienting; however the alerting network appears conserved. Conclusions: Our results support the thesis of a little specific attentional deficit in the schizophrenia or it puts in evidence the segregation of the three attentional networks. In recent years, reports of attentional deficits in schizophrenic patients and in their biological relatives have rapidly increased, including efforts to link endophenotypes to specific genes for this illness. Posner and col. have developed an Attention Network Test. That provides a separate measure for each of the three anatomically defined attention networks (alerting, orienting and executive control). The family association of these reported alterations supports the idea of a potential endophenotype in the schizophrenia.
Posters
psychiatric disorders, including not only psychotic symptoms but also nonpsychotic symptoms.
P17-6 N400 deficits from semantic matching of pictures in probands and first degree relatives from multiplex schizophrenia families
P17-4 Clinical application of the P300 component of event-related potentials
S. Guerra1 , M. Martin1 , M.A. Bobes1 , A. Ibanez1 , M. Valdes Sosa1 Department of Clinical Neurophysiology, Moron General Hospital. Ciego de Avila, Cuba
Y. Takahashi1 , A. Toyomaki1 , T. Koyama1 1 Dept. of Psychiatry, Hokkaido University Graduate School of Medicine, Sapporo, Japan
Objective: Endophenotypes is one emerging strategy in schizophrenia research that is being used to identify the functional importance of genetically transmitted, brain based deficits present in this disease. Currently, event-related potentials (ERPs) are timely used in this search. Several ERPs, including N400, present deficits in relation to schizophrenia. Methods: In order to assess the genetic liability of N400 as a possible endophenotype, a picture semantic-matching task (congruent and incongruent pairs of pictures) was performed by 21 unaffected firstdegree relatives of patients with schizophrenia, 21 DSM-IV diagnosed schizophrenia probands, and 21 control subjects, matched by age, gender and educational level. Probands and relatives were selected form Multiplex schizophrenia families. Results: Significantly reduced N400 amplitude for congruent categories in N400 was found in probands and relatives in relation to controls. The latency onset and the maximum peak latency of N400 were delayed in both, relatives and probands groups compared to control. The voltage maps of incongruous-minus-congruous difference indicate a more reduced right restricted negativity in probands and relatives, when compared to a wide extended bilateral negativity in controls. No general differences were found between patients and relatives. Conclusions: These results demonstrate an electrophysiological deficit in semantic match processing in clinically unaffected first degree relatives of patients with schizophrenia, suggesting a possible use of this marker as endophenotype.
Objective: Abnormality of P300 waveforms of event-related potentials (ERPs) has been suggested to represent an aspect of the pathophysiology of schizophrenia. However, very few attempts have been made at measuring P3b in not 2-tone but 3-tone oddball task. In the present study, we sought to compare P3b component elicited in between 2-tone and 3-tone oddball tasks. Furthermore, we examined EEG frequency characteristics which have been linked to specific cognitive functions such as stimulus encoding and selective attention during an auditory oddball task. We evaluated differences of these P3b and induced EEG frequency changes between schizophrenia patients and normal controls. Methods: EEG data were acquired from patients with schizophrenia (n = 20) and age-matched normal comparison participant (n = 20).EEG was recorded on both 2-tone and 3-tone task. To examine whether schizophrenic patients have abnormalities in frequency-domain, eventrelated alpha attenuation, as well as in time-domain EEG phenomena, such as event-related potential, we compared alpha power change and P300 elicited simultaneously in response to the presentation of target tones in an auditory oddball paradigm between patients with schizophrenia and normal controls. Results: Schizophrenia patients showed significantly reduced P3b amplitude at Pz compared to normal controls. There were tendency of different EEG frequency changes between schizophrenic patients and normal controls. Conclusions: These investigation are useful order to know schizophrenia patients. P17-5 Effects of vocalizing on auditory N1 component of event-related potentials in schizophrenic patients A. Iwanami1 , Y. Okajima1 , N. Kato1 1 Department of Psychiatry, Showa University School of Medicine, Japan Objective: Corollary discharge is a brain electrical activity associated with self-monitoring, which distinguishes self from others in thoughts or behaviors. Corollary discharge can be non-invasively assessed using eventrelated potential (ERP) recordings in humans. Some previous studies have revealed that the amplitude of the N1 component elicited during an “oddball” task is reduced while a healthy subject is vocalizing, which may index the effect of corollary discharge on auditory ERPs. In this study, we attempted to assess the effects of vocalizing on the N1 component during a passive oddball task in 10 healthy adults and 10 schizophrenic patients. Methods: Event-related potentials were recorded during a passive auditory task while subjects were silent, and while subjects were vocalizing. Subjects were presented with a series of 300 auditory stimuli with a fixed interstimulus interval of 1 sec. In the task, 85% of the stimuli were tones of 1 KHz, and the other 15% tones of 2 KHz. The stimulus intensity was 75 dBSPL. According to the international 10 20 system, the scalp electroencephalogram (EEG) was recorded. Vertical and horizontal electrooculograms (EOG) were recorded from electrodes placed below and at the outer canthus of the right eye. EEG samples were acquired every 1 msec from 100 msec before to 900 msec after the stimulus onset. The responses to frequent and rare tones and were averaged separately. N1 was defined as the most negative peak between 60 and 150 ms poststimulus. Amplitudes were measured with respect to an average voltage during the 100 ms prestimulus. Results and Conclusions: The amplitude of N1 component was lower during vocalizing than during the silent baseline condition in normal controls, but not in schizophrenic patients. These results may replicate that the auditory N1 component may reflect the effects of corollary discharge.
1
P17-7 Attentional network task in schizophrenic patients and their unaffected first-degree relatives: a potential endofenotype S. Guerra1 , J. Iglesias2 , M. Martin2 , R. Mendosa2 , M.D.L.A. Pedroso1 , M.A. Bobes2 1 Department of Clinical Neurophysiology, Moron General Hospital. Ciego de Avila, Cuba, 2 Department of Biological Psychiatry, Cuban Neuroscience Center, Havana, Cuba Objective: In this paper, we investigate through a study of family association the attentional performance in 26 schizophrenic patients, 30 unaffected first degree relatives and 30 healthy controls using the ANT. Methods: Our ANT is one combination of a spatial cueing task and a flanker task, it contains three experimental blocks with 60 trials each one and 12 conditions (4 cue levels by 3 target levels). We examine the efficiency of the segregated executive control, alerting and orienting networks by measuring how response latencies (reaction time) were modified by the cue position and the flanking stimuli. We also explore if these alteration attentionals are present in unaffected family members at a higher rate than in the general population (family association). Results: The ANOVA reveals main effects of flanker and cue condition and a significant interaction effect between flanker and study groups. The schizophrenic patients and their relatives had a longer median reaction time than the control group (1026.7; 1001.1 and 845.9 respectively). Finally, the ANT data revealed that the schizophrenic patients and their biological relatives differed significantly from the healthy control in terms of their conflict resolution and the orienting; however the alerting network appears conserved. Conclusions: Our results support the thesis of a little specific attentional deficit in the schizophrenia or it puts in evidence the segregation of the three attentional networks. In recent years, reports of attentional deficits in schizophrenic patients and in their biological relatives have rapidly increased, including efforts to link endophenotypes to specific genes for this illness. Posner and col. have developed an Attention Network Test. That provides a separate measure for each of the three anatomically defined attention networks (alerting, orienting and executive control). The family association of these reported alterations supports the idea of a potential endophenotype in the schizophrenia.