Short communicationRepeated microinjections into the medial prefrontal cortex (mPFC) impair extinction of conditioned place preference in mice

The medial prefrontal cortex (mPFC) is important for extinction of many behaviors including conditioned place preference (CPP). We examined the effects of intra-mPFC inactivation (with bupivacaine) on extinction of ethanol-induced CPP in mice. Injections of both bupivacaine and vehicle impaired extinction whereas no-surgery control mice extinguished normally. Consistent with recently reported effects of mPFC lesions, these data suggest that extinction was impaired by excessive mPFC damage induced by repeated intracranial infusions.

► Intra-mPFC bupivacaine and vehicle impaired extinction of ethanol-CPP. ► No-surgery control mice extinguished normally. ► Extinction was likely impaired by excessive mPFC damage caused by the infusions. ► These results support a role for the mPFC in extinction of EtOH-CPP. ► These findings caution the use of multiple intra-mPFC microinjections in mice.