P3-2-12. GABAA and glutamate receptor-mediated functions in the dorsolateral prefrontal cortex in patients with schizophrenia

Abstract

GABAergic and glutamatergic dysfunctions in the dorsolateral prefrontal cortex (DLPFC) are thought to be the crucial underlying pathophysiology in schizophrenia. The present study aimed to investigate the GABAA (i.e., short interval intracortical inhibition: SICI) and glutamate (intracortical facilitation: ICF) receptor-mediated functions from the DLPFC in patients with schizophrenia compared to healthy controls, applying the paired-pulse transcranial magnetic stimulation (TMS) paradigms combined with high-spec electroencephalography (EEG). Given that GABAergic and glutamatergic activities contribute to cognitive/clinical functions, the relationship among the modulations of TMS-evoked potential (TEP) by the SICI/ICF and cognitive/clinical measures were explored in patients group. Compared to healthy controls, patients with schizophrenia showed attenuated inhibition by SICI on P60 TEP and attenuated facilitation by ICF on P60 and N100 TEPs. Further, the modulation on P60 TEP by the SICI was correlated with the longest span of the Letter-Number Span Test, while the modulation of N100 TEP by the ICF was correlated with the total score of the Positive and Negative Syndrome Scale in the patients group. These prefrontal GABAAergic and glutamatergic dysfunctions may indicate the underlying pathophysiology of schizophrenia.