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Neuron. 2014 Oct 1;84(1):177-189. doi: 10.1016/j.neuron.2014.08.033. Epub 2014 Sep 11.

Overriding phasic dopamine signals redirects action selection during risk/reward decision making.

Author information

1
Department of Psychology and Brain Research Centre, University of British Columbia, Vancouver, BC V6T 1Z4, Canada.
2
Department of Psychology and Brain Research Centre, University of British Columbia, Vancouver, BC V6T 1Z4, Canada. Electronic address: floresco@psych.ubc.ca.

Abstract

Phasic increases and decreases in dopamine (DA) transmission encode reward prediction errors thought to facilitate reward-related learning, yet how these signals guide action selection in more complex situations requiring evaluation of different reward remains unclear. We manipulated phasic DA signals while rats performed a risk/reward decision-making task, using temporally discrete stimulation of either the lateral habenula (LHb) or rostromedial tegmental nucleus (RMTg) to suppress DA bursts (confirmed with neurophysiological studies) or the ventral tegmental area (VTA) to override phasic dips. When rats chose between small/certain and larger/risky rewards, LHb or RMTg stimulation, time-locked to delivery of one of these rewards, redirected bias toward the alternative option, whereas VTA stimulation after non rewarded choices increased risky choice. LHb stimulation prior to choices shifted bias away from more preferred options. Thus, phasic DA signals provide feedback on whether recent actions were rewarded to update decision policies and direct actions toward more desirable reward.

PMID:
25220811
DOI:
10.1016/j.neuron.2014.08.033
[Indexed for MEDLINE]
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