Behavioural brain research
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Intracranial self-administration (ICSA) and intracranial place conditioning (ICPC) methodologies have been mainly used to study drug reward mechanisms, but they have also been applied toward examining brain reward mechanisms. ICSA studies in rodents have established that the ventral tegmental area (VTA) is a site supporting morphine and ethanol reinforcement. ICPC studies confirmed that injection of morphine into the VTA produces conditioned place preference (CPP). ⋯ Among these regions, ICPC findings suggest that cocaine and amphetamine are rewarding in the rostral ventral pallidum (VP); ICSA and ICPC studies indicate that morphine is rewarding in the dorsal hippocampus, central gray and lateral hypothalamus. Finally, substance P mediated systems within the caudal VP (nucleus basalis magnocellularis) and serotonin systems of the dorsal and median raphe nuclei may also be important anatomical components involved in brain reward mechanisms. Overall, the ICSA and ICPC studies indicate that there are a number of receptors, neuronal pathways, and discrete CNS sites involved in brain reward mechanisms.