Neural Differentiation of Expected Reward and Risk in Human Subcortical Structures
Abstract
In decision-making under uncertainty, economic studies emphasize the importance of risk in addition to expected reward. Studies in neuroscience focus on expected reward and learning rather than risk. We combined functional imaging with a simple gambling task to vary expected reward and risk simultaneously and in an uncorrelated manner. Drawing on financial decision theory, we modeled expected reward as mathematical expectation of reward, and risk as reward variance. Activations in dopaminoceptive structures correlated with both mathematical parameters. These activations differentiated spatially and temporally. Temporally, the activation related to expected reward was immediate, while the activation related to risk was delayed. Analyses confirmed that our paradigm minimized confounds from learning, motivation, and salience. These results suggest that the primary task of the dopaminergic system is to convey signals of upcoming stochastic rewards, such as expected reward and risk, beyond its role in learning, motivation, and salience.
Additional Information
Copyright © 2006 Elsevier Inc. Received December 15, 2005; Revised May 3, 2006; Accepted June 26, 2006; Published August 2, 2006. This work was supported by NSF Grant 0093757, the David and Lucile Packard Foundation, and the Gordon and Betty Moore Foundation. We thank John O'Doherty and members of the Social Cognitive Neuroscience Laboratory for helpful comments. We thank Steven Flaherty for technical assistance and three anonymous reviewers whose comments resulted in considerable improvement of the paper.Attached Files
Supplemental Material - PIIS0896627306005046_mmc1.pdf
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Additional details
- Eprint ID
- 40333
- DOI
- 10.1016/j.neuron.2006.06.024
- Resolver ID
- CaltechAUTHORS:20130816-103132896
- 0093757
- NSF
- David and Lucile Packard Foundation
- Gordon and Betty Moore Foundation
- Created
-
2008-02-05Created from EPrint's datestamp field
- Updated
-
2023-09-26Created from EPrint's last_modified field
- Caltech groups
- Koch Laboratory (KLAB)