Abstract
It is well known that systemically administered phencyclidine (PCP) enhances theta activity of cortical EEG with augmentation of locomotor activity and stereotypic behavior in unanesthetized animals. Recent studies have shown that tonic activation of the medial prefrontal cortex (mPFC) is a key factor for inducing behavioral abnormalities by systemic PCP. However, it is not clear whether tonic activation of the mPFC necessarily accompanies increased synchronization of cortical EEG. Here, we examined this question by comparing systemic administration of PCP with local one into the ventral hippocampus in freely moving rats. Though both administration of PCP produced tonic activation of mPFC neurons with behavioral activation, only systemic PCP induced clear enhancement of theta activity. These results indicate that activation of the mPFC by PCP may be independent of enhanced synchronization in slow wave EEG. [Jpn J Physiol 55 Suppl:S234 (2005)]
