[Frontiers in Bioscience E5, 273-288, January 1, 2013]

Rapid dopamine dynamics in the accumbens core and shell: Learning and action

Michael P. Saddoris1, Jonathan A. Sugam1, Fabio Cacciapaglia1,2, Regina M. Carelli1,3

1Department of Psychology, University of North Carolina, Chapel Hill, NC 27599,2Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599, 3Neuroscience Center, University of North Carolina, Chapel Hill, NC 27599

TABLE OF CONTENTS

1. Abstract
2. Introduction
3. Anatomy of the dopamine system: General overview
4. Dopamine and neural encoding in the NAc: Critical components of learning
5. Reward processing and the NAc
6. Pavlovian cue learning
7. Dopamine detection during goal-directed action
8. Higher-order schedules of reinforcement and the NAc
9. NAc DA and decision-making
10. Microcircuit analysis of DA influence on NAc function: Simultaneous FSCV and electrophysiology during learning
11. Building circuits of motivation and learning: BLA influences on NAc activity during behavior
12. Conclusions: Towards a theory of NAc core and shell differences
13. Acknowledgments:
14. References

1. ABSTRACT

The catecholamine dopamine (DA) has been implicated in a host of neural processes as diverse as schizophrenia, parkinsonism and reward encoding. Importantly, these distinct features of DA function are due in large part to separate neural circuits involving connections arising from different DA-releasing nuclei and projections to separate afferent targets. Emerging data has suggested that this same principle of separate neural circuits may be applicable within structural subregions, such as the core and shell of the nucleus accumbens (NAc). Further, DA may act selectively on smaller ensembles of cells (or, microcircuits) via differential DA receptor density and distinct inputs and outputs of the microcircuits, thus enabling new learning about Pavlovian cues, instrumental responses, subjective reward processing and decision-making. In this review, by taking advantage of studies using subsecond voltammetric techniques in behaving animals to study how rapid changes in DA levels affect behavior, we examine the spatial and temporal features of DA release and how it relates to both normal learning and similarities to pathological learning in the form of addiction.