Electrophysiology of the prefrontal cortex in healthy controls and schizophrenic patients: a review

Prefrontal brain regions, in particular the anterior cingular gyrus (ACG), are altered in chronic schizophrenic patients and also play a pivotal role in physiological mechanisms of response control. A cued Continuous Performa nce Test (CPT) is a suitable paradigm for the investigation of response con trol, as it contains its fundamental mechanisms, i.e. the execution (Go) an d the inhibition (NoGo) of an anticipated motor response. Previous electrop hysiological investigations in healthy subjects during CPT execution reveal ed that the gravity center (centroid) of the event-related potential (ERP) elicited during the NoGo-condition is located more anterior as compared to the Go-condition in every single case. Moreover, by means of an electrophys iological source location method this NoGo-anteriorisation phenomenon (NGA) has been attributed to a strong brain electrical NoGo-hyperactivity locate d in prefrontal brain areas (ACG). Furthermore, the NGA has a superior test -retest reliability, a very high interindividual stability and is independe nt from age- and gender-effects. Systematic schizophrenic patients were cha racterized by a significantly diminished NGA indicating a dysfunction of pr efrontal brain areas including the ACG. Based on these findings, the NGA ha s to be considered as a first electrophysiological measure for the quantita tive assessment of ACG-function within a response control paradigm. Hopeful ly, this biological parameter will contribute to the elucidation of the eti opathogenetical background in different schizophrenic diseases.