Dopamine-Glutamate Interactions in Reward-Related Incentive Learning

Abstract

Extensive evidence implicates the neurotransmitter dopamine (DA) in reward-related incentive learning (for reviews, see refs. 1–13). DA projections to the nucleus accumbens (NAc; refs. 14–17), striatum (18), amygdala (19), and medial prefrontal cortex (mPFC; ref. (20) have been shown to be involved. In recent years, researchers have begun to focus on the neurochemical mechanisms underlying the role of DA in learning and significant advances have been made (21–23). Many data suggest that DA afferents interact with glutamatergic (Glu) afferents common to the same cell when reward-related learning occurs (see ref. 22). Results further suggest that a number of signaling molecules activated by Glu and DA synaptic transmission interact to bring about short-term and long-term alterations that mediate the neurochemical and structural changes that form the basis of reward-related incentive learning (see ref. 22). In this chapter, we will review some of the studies examining the role of DA and especially Glu neurotransmission in reward-related learning. This will be followed by a discussion of evidence that provides a basis for understanding the DA-Glu interactions and the signaling pathways that mediate the effects of reward on behavior. Finally, the role of Glu in reward-related learning will be considered from the point of view of this evidence.