1Schizophr. Res. 2010 Jun 119: 191-7
TitleDysfunctional gamma-band activity during face structural processing in schizophrenia patients.
AbstractThis study investigated gamma-band activity (GBA) and its phase synchrony in schizophrenia patients viewing human faces. Twenty-five schizophrenia patients were compared with 25 normal controls. Event-related potentials were recorded from all participants while they were viewing emotionally neutral faces. The spectral power and phase synchrony in the frequency band from 30 to 55 Hz were analyzed in midline electrodes (FCz, Cz, CPz, Pz, and POz). Three windows of interest, which showed discernable GBA differences between schizophrenia patients and normal controls, were selected by visual inspection: 0-100 ms (30-33 Hz), 250-300 ms (34-38 Hz), and 700-800 ms (40-45 Hz). And the phase synchrony of gamma band was analyzed. Repeated-measures ANOVA revealed that the GBA was lower in schizophrenia patients than in normal controls. Also there were significant location and time differences in GBA. GBA was significantly lower in the schizophrenia patients than in the normal controls at around 700-800 ms at the FCz electrode. The frontal (FCz) and central (Cz) GBA were significantly correlated with the number of hospitalization, and the negative symptoms of schizophrenia, respectively. The phase synchronization was significantly lower at 200-300 ms in the schizophrenia patients than in the normal controls. These findings suggest that the schizophrenia patients have impaired GBA and gamma-band synchronization during face perception. Furthermore, our results also suggest that the decreased GBA observed at the midline cortex of schizophrenia patients is closely related to their negative symptoms and disease progress.
SCZ Keywordsschizophrenia
2Seishin Shinkeigaku Zasshi 2012 -1 114: 629-46
Title[Endophenotypes in schizophrenia: a review of electrophysiological studies].
Abstractschizophrenia patients consistently show some deficiency in electrophysiological measures, such as PPI (Prepulse Inhibition), ERP (Event-Related Potential) components (mismatch negativity, P50, P300), EEG (Electroencephalography), and MEG (Magnetoencephalography). These components have been intensively studied as quantitative biological markers (i.e., endophenotypes) for psychiatric disorders. Recently brain oscillations, especially gamma (30-80 Hz) band activity (GBA), are being increasingly investigated as new candidate endophenotypes. In this review, we summarize the current status, perspective, and limitations of representative paradigms for investigating abnormal electrophysiological components of schizophrenia, along with relevant genetic polymorphism.
SCZ Keywordsschizophrenia
3Psychiatry Investig 2016 May 13: 349-59
TitleDysfunctional Patterns of Gamma-Band Activity in Response to Human Faces Compared to Non-Facial Stimuli in Patients with Schizophrenia.
AbstractHealthy individuals show stronger gamma-band activities (GBAs) for socially relevant stimuli (human faces) than for non-relevant ones. This study aimed to examine whether this gamma-band preference occurs in patients with schizophrenia.
EEG was recorded for 24 patients with schizophrenia and 23 healthy controls while they viewed pictures of human faces, chairs, and nature scenes. The spectral powers of high-beta (20-30 Hz) and gamma (30-80 Hz) frequencies were analyzed along 3 midline cortical regions, and phase synchronization was calculated.
Compared to the response to non-facial stimuli, higher event related deactivation to facial stimuli was observed for the high-beta frequency across groups. For the gamma frequency, early-stage GBA was increased and late-stage GBA was decreased for all 3 stimuli in patients with schizophrenia compared to healthy controls. Preferential GBA patterns (100-200 and 200-300 ms) were found in healthy controls, but not in patients with schizophrenia. Significant correlation existed between negative symptoms and GBA in the frontal region for chair and scene stimuli. There was no significant intergroup difference in phase synchronization pattern.
Our results suggest that patients with schizophrenia have deficits in the preferential pattern of GBA for human faces and the deficits in the preferential pattern were mainly influenced by over-response to socially non-relevant stimuli.
SCZ Keywordsschizophrenia