Adaptive coding of reward value by dopamine neurons.

Department of Anatomy, University of Cambridge, Downing Street, Cambridge CB2 3DY, UK, and Institute of Physiology, University of Fribourg, CH-1700 Fribourg, Switzerland.
Science (Impact Factor: 31.48). 04/2005; 307(5715):1642-5. DOI: 10.1126/science.1105370
Source: PubMed

ABSTRACT It is important for animals to estimate the value of rewards as accurately as possible. Because the number of potential reward values is very large, it is necessary that the brain's limited resources be allocated so as to discriminate better among more likely reward outcomes at the expense of less likely outcomes. We found that midbrain dopamine neurons rapidly adapted to the information provided by reward-predicting stimuli. Responses shifted relative to the expected reward value, and the gain adjusted to the variance of reward value. In this way, dopamine neurons maintained their reward sensitivity over a large range of reward values.

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