Chapter 19. Diversity of encoding: Reward to aversion

This chapter discusses diversity in the signaling properties of dopamine neurons, with a particular focus on their activity and function in response to reward and threat. While dopamine neurons were traditionally reported to be excited by reward-related events, accumulating evidence indicates that certain dopamine neurons are excited not only by reward but also by neutral or even aversive stimuli. Recent studies have mapped these noncanonical activity patterns onto subpopulations of dopamine neurons identified by their projection targets. In this chapter, we will discuss distinct patterns of activity in projection-specific dopamine neuron subpopulations and their associated functions in various behavioral contexts. Throughout, we will consider how the distinct response profiles and functions of dopamine neuron subpopulations may be reconciled within common computational frameworks.