Rule learning and reward contingency are associated with dissociable patterns of dopamine activation in the rat prefrontal cortex, nucleus accumbens, and dorsal striatum.

Full Abstract

The midbrain dopamine system has been ascribed roles in reward expectancy, error detection, prediction, and memory. However, these theories typically do not differentiate between dopamine response and action in different forebrain terminal fields. We measured dopamine release in the prefrontal cortex (PFC), nucleus accumbens (NAc), and dorsal striatum (DS) of rats exposed to the same maze apparatus under three behavioral conditions:
a set-shift task in which reward depended on discrimination learning and extradimensional set-shifting, a yoked condition in which reward was intermittent and not under the control of the subject, and a "reward-retrieval" variant in which reward was certain on every trial. We found dissociable patterns of dopamine release associated with learning, uncertainty, and reward. Dopamine increased in all three regions when reward was contingent on rule learning and shifting or was uncertain. These increases were sustained after behavior. There was a significant correlation between the magnitude of increase in PFC dopamine and the rapidity with which rats shifted between discrimination rules. In the yoke condition, in which the receipt of reward was always uncertain, the opposite relationship between dopamine levels and likelihood of reward was observed. Predictable, noncontingent reward was associated with increased dopamine levels in the NAc and DS. In contrast, PFC dopamine did not increase significantly above baseline levels. Thus, the dopaminergic projections to the PFC and nucleus accumbens were selectively, yet differentially, activated in situations of uncertainty and cognitive demand, whereas the dopaminergic projection to the DS responded independently of task differences in learning and reward.

Learn Faster Today Improve your study skills

Author information

Author/s: Stefani, Mark R (MR); Moghaddam, Bita (B);

Affiliation: Psychology Department, Middlebury College, Middlebury, Vermont 05753, USA. stefani(-atsign-)middlebury.edu

Grants: R01-MH48404 (Agency:NIMH NIH HHS) ; R21-MH65026 (Agency:NIMH NIH HHS)

Journal and publication information

Publication Type: Journal Article; Research Support, N.I.H., Extramural

Journal: The Journal of neuroscience : the official journal of the Society for Neuroscience (J Neurosci), published in United States. (Language: eng)

Reference: 2006-Aug; vol 26 (issue 34) : pp 8810-8

Dates: Created 2006/08/24; Completed 2006/09/28; Revised 2007/11/14;

PMID: 16928870, status: MEDLINE (last retrieval date: 12/26/2008)

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

External Links for this article (including full text providers, if available):

Click Electronic Full-text Provider Links to see options for finding the electronic full text links to this article. Note there may be a subscription or fee required for access to the full text. See our FAQ for information on finding FREE full text articles.

This article may also be located in paper journal collections available in many libraries. Use the Journal and Publication Information above to find the full article.

MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Animals
Behavior, Animal - physiology
Corpus Striatum - metabolism; physiology
Discrimination Learning - physiology
Dopamine - metabolism; physiology
Goals
Male

Maze Learning - physiology
Nucleus Accumbens - metabolism; physiology
Prefrontal Cortex - metabolism; physiology
Rats
Rats, Sprague-Dawley
Reward
Uncertainty

Associated Chemicals: Dopamine (51-61-6)

These are the highest related articles currently in the database:

See 100+ related articles.