Neurochemistry and molecular neurobiology of reward

The reward system consists of multiple interactive neural systems. This chapter provides an overview of the neurotransmitters and brain regions involved with reward. The neural systems important for reward include brain areas involved in learning that a stimulus is rewarding or associated with reward and separate neural systems that mediate wanting and liking for a stimulus. The ascending dopamine systems are thought to be necessary for wanting, whereas liking is mediated by GABAergic and opioid neurons in the nucleus accumbens shell in association with the ventral pallidum and parabrachial nucleus. The specific systems and molecular mechanisms mediating food reward versus the rewarding aspects of drugs of abuse are discussed. Sex differences in the reward system are highlighted.