Update on electrophysiology in schizophrenia

Event-related potentials (ERPs) provide a non-invasive, functional method to evaluate neural activation and cognitive processes in schizophrenia, with a temporal resolution in the millisecond range, literally at the speed of thought. Auditory ERP components tested in schizophrenia, in order of latency of occurrence, include the P50 sensory gating response, the mismatch negativity, P300, and the N400 component. Abnormalities in these components demonstrate pervasive disruption of auditory processing as early as 50 milliseconds after stimulus onset. All of these abnormalities appear to tasks which require sensory memory or working memory operations. The anatomic substrates for these ERP components probably include the posterior superior temporal gyrus and medial temporal lobe structures. P300 topographic asymmetries have been associated with left posterior superior temporal gyrus abnormalities. Future work will focus on relating ERP abnormalities to specific neural circuit disturbances in this disorder.