Reward Value Coding Distinct From Risk Attitude-Related Uncertainty Coding in Human Reward Systems

Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, England, United Kingdom
Journal of Neurophysiology (Impact Factor: 2.89). 03/2007; 97(2):1621-32. DOI: 10.1152/jn.00745.2006
Source: PubMed


When deciding between different options, individuals are guided by the expected (mean) value of the different outcomes and by the associated degrees of uncertainty. We used functional magnetic resonance imaging to identify brain activations coding the key decision parameters of expected value (magnitude and probability) separately from uncertainty (statistical variance) of monetary rewards. Participants discriminated behaviorally between stimuli associated with different expected values and uncertainty. Stimuli associated with higher expected values elicited monotonically increasing activations in distinct regions of the striatum, irrespective of different combinations of magnitude and probability. Stimuli associated with higher uncertainty (variance) elicited increasing activations in the lateral orbitofrontal cortex. Uncertainty-related activations covaried with individual risk aversion in lateral orbitofrontal regions and risk-seeking in more medial areas. Furthermore, activations in expected value-coding regions in prefrontal cortex covaried differentially with uncertainty depending on risk attitudes of individual participants, suggesting that separate prefrontal regions are involved in risk aversion and seeking. These data demonstrate the distinct coding in key reward structures of the two basic and crucial decision parameters, expected value, and uncertainty.

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Available from: Raymond J Dolan, Apr 03, 2015
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    • "It is possible that different activation patterns in the two regions bias the weight of the aspects of gamble information and subsequently result in different choices. In addition , as the caudate is associated with a broad range of information processing in a gamble task such as anticipatory risk (Preuschoff et al., 2006; Venkatraman et al., 2007), reward magnitude, expected value (Kable and Glimcher, 2007; Tobler et al., 2007), and action selection (Mullette-Gillman et al., 2011), one interpretation of our result is that the caudate integrates various information, including pre-stimulus endogenous fluctuations, to generate a choice tendency between risk gamble and certainty outcome. Finally, after the gamble information appeared , the right NAcc was found to reflect the gamble choices, suggesting that people were anticipating the gains of a gamble after choice. "
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    • "During decision processing, neuroimaging methods, such as functional magnetic resonance imaging (fMRI), have identified the role of prefrontal areas (such as the dorsolateral, lateral and ventromedial prefrontal cortex, orbitofrontal and the anterior cingulate cortex) and subcortical areas (such as the striatum and the amygdala) in encoding the two main components of a subjective value signal, i.e., its risk probability and expected value (Fukunaga et al., 2012; Li et al., 2010; Lighthall et al., 2012; Rao et al., 2008; Schonberg et al., 2012). Typically, increasing blood-oxygen-level-dependent (BOLD) signals in these areas encode risk with respect to uncertainty, variance, or volatility (Huettel et al., 2006, 2005; Knutson et al., 2005; Preuschoff et al., 2006; Tobler et al., 2007) and encode expected value with respect to magnitude, probability, and their combination (Knutson et al., 2005; Preuschoff et al., 2006; Tobler et al., 2007). "
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    • "Reward anticipation refers to dopaminergic activation prior to reward, while outcome evaluation refers to dopaminergic activation after the reward. This article reviews evidence on dopaminergic dysfunctions in reward anticipation and outcome evaluation in gambling disorder from two vantage points: a model of reward prediction and reward prediction error by Schultz et al. (Fiorillo et al., 2003; Schultz, 2006; Tobler et al., 2007; Schultz et al., 2008), and a model of “wanting” and “linking” by Robinson and Berridge (Robinson and Berridge, 1993, 2000, 2003, 2008; Berridge and Aldridge, 2008; Berridge et al., 2009). It is suggested that gambling disorder may provide a “model disorder” of addiction for the two approaches, which is not confounded by ingestion of exogenous substances. "
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