Phasic nucleus accumbens dopamine release encodes effort- and delay-related costs

Biol Psychiatry. 2010 Aug 1;68(3):306-9. doi: 10.1016/j.biopsych.2010.03.026. Epub 2010 May 10.

Abstract

Background: Optimal decision-making requires that organisms correctly evaluate both the costs and benefits of potential choices. Dopamine transmission within the nucleus accumbens (NAc) has been heavily implicated in reward-learning and decision-making, but it is unclear how dopamine release might contribute to decisions that involve costs.

Methods: Cost-based decision-making was examined in rats trained to associate visual cues with either immediate or delayed rewards (delay manipulation) or low-effort or high-effort rewards (effort manipulation). After training, dopamine concentration within the NAc was monitored on a rapid time scale with fast-scan cyclic voltammetry.

Results: Animals exhibited a preference for immediate or low-effort rewards over delayed or high-effort rewards of equal magnitude. Reward-predictive cues but not response execution or reward delivery evoked increases in NAc dopamine concentration. When only one response option was available, cue-evoked dopamine release reflected the value of the future reward, with larger increases in dopamine signaling higher-value rewards. In contrast, when both options were presented simultaneously, dopamine signaled the better of two options, regardless of the future choice.

Conclusions: Phasic dopamine signals in the NAc reflect two different types of reward cost and encode potential rather than chosen value under choice situations.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Choice Behavior / physiology*
  • Decision Making / physiology*
  • Dopamine / metabolism*
  • Male
  • Nucleus Accumbens / metabolism*
  • Periodicity
  • Probability Learning*
  • Rats
  • Rats, Sprague-Dawley
  • Reward

Substances

  • Dopamine