Aberrant temporal behavior of discrete mismatch negativity generators in patients with schizophrenia and subjects at clinical high risk for psychosis

Poster B9, Friday, October 21, 11:30 am - 1:00 pm, Le Baron

Minah Kim1, Kang Ik Kevin Cho2, Youngwoo Bryan Yoon2, Tae Young Lee3, Sung Nyun Kim1, Jun Soo Kwon1,2,4; 1Department of Psychiatry, Seoul National University College of Medicine, Seoul, Republic of Korea, 2Department of Brain and Cognitive Science, Seoul National University College of Natural Science, Seoul, Republic of Korea, 3Department of Neuropsychiatry, Seoul National University Hospital, Seoul, Republic of Korea, 4Institute of Human Behavioral Medicine, SNU-MRC, Seoul, Republic of Korea

Purpose: Mismatch negativity (MMN) multiple generators in healthy subjects have been shown separate time behaviors which suggests functional connections between MMN related brain regions. Although disconnection has been thought as a core pathophysiologic mechanism of schizophrenia, little is known about the temporal association of MMN multiple generators in schizophrenia and prodromal psychosis. Thus, we aimed to investigate disruptions in pre-attentive level functional connectivity in patients with schizophrenia and subjects at clinical high risk (CHR) for psychosis. Materials and methods: Duration-deviant MMN were assessed in 29 schizophrenia patients, 40 CHR subjects, and 47 healthy controls (HCs). Individual realistic head model, incorporating anatomical data from personal magnetic resonance image, was constructed. Minimum L2 norm algorithm was used to generate current source density (CSD) model of MMN response over time. The strength of MMN CSD and its time course were calculated separately for frontal and temporal cortices, then were compared across brain regions and groups. Results: Schizophrenia patients and CHR subjects presented reduced MMN CSD strengths compared to HCs not only in the temporal cortex but also in the frontal cortex. We also found significant time delay of frontal generator activity relative to temporal generator activity in HCs. However, those temporo-frontal sequential activities of MMN generators were disrupted in both schizophrenia and CHR groups. Conclusions: There were generator impairments and functional disconnection in MMN related brain regions even prior to the onset of psychosis. From these results, we suggest that aberrant MMN generator activity might be helpful in revealing schizophrenia pathophysiology.

Topic Area: Electrophysiology

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