P3 topography in psychiatry and psychopharmacology.

Endogenous components of event related potentials are of particular interest in psychiatric diseases because of their relations to cognitive and behavioral processes. We studied the topography of these potentials in order to find out whether there are different scalp distributions in schizophrenic and depressive patients in relation to the psychopathological state and compared to normal controls. Furthermore variations of the topographical scalp distribution of P300 in normal volunteers after administration of physostigmine and biperiden was investigated. We demonstrated a clear relationship of the P300 amplitude with the negative symptom axis and found different topographical scalp distributions in different groups and experimental conditions. Topography of event related potentials is therefore a promising field of investigation for a better understanding of psychiatric disorders.