204. Dynamic Causal Modeling of Pitch MMN in First Episode Psychosis Reveals Impaired A1-STG Communication and Selective Dysfunction of NMDA Receptor

Mismatch Negativity (MMN) is severely reduced to pitch (pMMN) and to duration (dMMN) deviant stimuli in schizophrenia (SZ). However, it is unclear if MMN is reduced in first episode psychosis and when the potential underlying pathophysiology starts. DCM allows inferences about biological processes in the brain from sensor-level data and is designed to explain, mechanistically, differences in the auditory network of deviance detection between groups that sensor-based analyses may miss.