Objectives This study examined the responses to standard stimuli to investigate the mechanisms underlying mismatch negativity (MMN) impairments in schizophrenia. Methods We obtained MMN data from 68 patients diagnosed with schizophrenia or schizoaffective disorder and 38 healthy controls and analyzed the electrophysiological activity of the responses to two standard stimuli before deviants using time-frequency methods. Results As a result of RM ANOVA at evoked alpha power, there were differences not only between- subjects (F1,104=4.35, p<0.05) but also within-subjects (F1,104=8.62, p<0.01) without groupby- stimulus interaction (F1,104=1.70, p=0.20). But at single-trial alpha power, there was a difference not between-subjects (F1,104=3.81, p=0.054), but only within-subjects (F1,104=10.14, p<0.01) with significant group-by-stimulus interaction (F1,104=5.71, p<0.05). Moreover, between-group differences were significant in evoked alpha power (t104=2.02, p<0.05, d=0.41) and single-trial alpha power (t104=2.49, p<0.01, d=0.50) to standard stimuli presented not at the first instance but second. According to the order that the two standards presented, there were increases of evoked alpha power (t37=-2.54, p<0.05, d=0.58) and single-trial alpha power (t37=-3.41, p<0.01, d=0.78) in only the healthy controls. The positive correlations were shown in clinical features between years of education completed and event-related potential amplitude at 100 ms to both standard stimuli (Each Pearson Corr.: r=0.22, p<0.05). Conclusion These outputs suggest that the P1 alpha oscillation to standards is associated with deficits in the inhibitory control of selective attention relative to cognitive dysfunction in schizophrenia. We could also hypothesize that these deficits are involved in computing prediction errors based on the predictive coding perspective. However, further studies on this hypothesis are necessary.
Objectives This study examined the responses to standard stimuli to investigate the mechanisms underlying mismatch negativity (MMN) impairments in schizophrenia. Methods We obtained MMN data from 68 patients diagnosed with schizophrenia or schizoaffective disorder and 38 healthy controls and analyzed the electrophysiological activity of the responses to two standard stimuli before deviants using time-frequency methods. Results As a result of RM ANOVA at evoked alpha power, there were differences not only between- subjects (F1,104=4.35, p<0.05) but also within-subjects (F1,104=8.62, p<0.01) without groupby- stimulus interaction (F1,104=1.70, p=0.20). But at single-trial alpha power, there was a difference not between-subjects (F1,104=3.81, p=0.054), but only within-subjects (F1,104=10.14, p<0.01) with significant group-by-stimulus interaction (F1,104=5.71, p<0.05). Moreover, between-group differences were significant in evoked alpha power (t104=2.02, p<0.05, d=0.41) and single-trial alpha power (t104=2.49, p<0.01, d=0.50) to standard stimuli presented not at the first instance but second. According to the order that the two standards presented, there were increases of evoked alpha power (t37=-2.54, p<0.05, d=0.58) and single-trial alpha power (t37=-3.41, p<0.01, d=0.78) in only the healthy controls. The positive correlations were shown in clinical features between years of education completed and event-related potential amplitude at 100 ms to both standard stimuli (Each Pearson Corr.: r=0.22, p<0.05). Conclusion These outputs suggest that the P1 alpha oscillation to standards is associated with deficits in the inhibitory control of selective attention relative to cognitive dysfunction in schizophrenia. We could also hypothesize that these deficits are involved in computing prediction errors based on the predictive coding perspective. However, further studies on this hypothesis are necessary.
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