Abnormal P600 in heroin addicts with prolonged abstinence elicited during a working memory test

The P600 component of event-related potentials, believed to be generated by anterior cingulate gyrus and basal ganglia, is considered as an index of a spects of second-pass parsing processes of information processing, having m uch in common with working memory (WM) systems. Moreover, dysfunction of th ese brain structures as well as WM deficits have been implicated in the pat hophysiology of opioid addicts. The present study is focused on P600 elicit ed during a WM test in twenty heroin addicts with prolonged abstinence comp ared with an equal number of healthy controls. The results showed significa ntly prolonged latencies at right hemisphere, specifically at F rho2 abduct ion. Moreover, memory performance of patients did not differ from that of n ormal controls. These findings may indicate that abstinent heroin addicts m anifest abnormal aspects of second-pass parsing processes as are reflected by the P600 latencies, elicited during a WM test. Additionally, the P600 mi ght serve as a valuable investigative tool for a more comprehensive underst anding of the neurobiological substrate of drug abuse. NeuroReport 12:1773- 1778 (C) 2001 Lippincott Williams & Wilkins.