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: 33.61). 04/2005; 307(5715):1642-5. DOI: 10.1126/science.1105370
Source: PubMed


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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Available from: Christopher D Fiorillo, Jul 21, 2015
    • "However, it remains an open issue which neural mechanisms underlie these deficits. Theoretical principles of efficient information processing and empirical findings in single cells suggest that in order to efficiently represent all of the possible rewards, reward-sensitive neurons adapt their coding range dynamically to the current reward context [1] [2]. A reduction in adaptive coding would affect the accurate representation of rewards and could potentially lie at the root of many dysfunctional reward processes in schizophrenia. "

    • "In these brain structures, differences in dopamine activation are linked to the processing of reward salience and magnitude (Bromberg-Martin et al. 2010). Changes in dopamine activation are linked with reinforcing the value and salience of stimuli (Schultz 1998), enabling behavioral change in response to environment (Tobler et al. 2005), and anticipating rewards (Kelley et al. 2005). For example, dopamine activation is related to the stimulatory and rewarding effects of alcohol consumption (Littleton and Little 1994; Samson and Harris 1992). "
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    • "The phasic dopamine value response increases with increasing objective, physical reward parameters including amount, probability, and statistically expected value (Fiorillo et al., 2003; Tobler et al., 2005). However, physical reward value also depends on the molecules in the reward, which differ between different reward types and substances. "
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