Directed coherence of EEG on ICSS rats with methamphetamine-induced hyperactivity and stereotyped behavior.

Methamphetamine (MAP) can reinforce intracranial self-stimulation (ICSS) in rats, that is, reward-seeking behavior. However, the ICSS can be inhibited by the stereotyped behavior induced by MAP. This study was designed to observe the mutual information flow between prefrontal cortex (PFC) and ventral tegmental area (VTA) using directed coherence (DC) analysis during the hyperactivity and stereotyped behavior induced by administration of MAP (a derivative of amphetamine). The DC from PFC to VTA increased at 5-7 Hz in the hyperactivity as compared to the stereotypy. In contrast, enhanced information flow from VTA to PFC was observed in the stereotypy as compared to the hyperactivity. We found a reciprocal information flow between PFC and VTA corresponding to the hyperactivity and stereotyped behavior that was induced by administration of MAP.