Dopamine-associated cached values are not sufficient as the basis for action selection.

Autor:	Hollon NG; Departments of Psychiatry and Behavioral Sciences and Pharmacology and Graduate Program in Neurobiology and Behavior, University of Washington, Seattle, WA 98195; and., Arnold MM; Departments of Psychiatry and Behavioral Sciences and Pharmacology and., Gan JO; Departments of Psychiatry and Behavioral Sciences and Pharmacology and Graduate Program in Neurobiology and Behavior, University of Washington, Seattle, WA 98195; and., Walton ME; Departments of Psychiatry and Behavioral Sciences and Department of Experimental Psychology, University of Oxford, Oxford OX1 3UD, United Kingdom., Phillips PE; Departments of Psychiatry and Behavioral Sciences and Pharmacology and Graduate Program in Neurobiology and Behavior, University of Washington, Seattle, WA 98195; and pemp@uw.edu.
Jazyk:	angličtina
Zdroj:	Proceedings of the National Academy of Sciences of the United States of America [Proc Natl Acad Sci U S A] 2014 Dec 23; Vol. 111 (51), pp. 18357-62. Date of Electronic Publication: 2014 Dec 08.
DOI:	10.1073/pnas.1419770111
Abstrakt:	Phasic dopamine transmission is posited to act as a critical teaching signal that updates the stored (or "cached") values assigned to reward-predictive stimuli and actions. It is widely hypothesized that these cached values determine the selection among multiple courses of action, a premise that has provided a foundation for contemporary theories of decision making. In the current work we used fast-scan cyclic voltammetry to probe dopamine-associated cached values from cue-evoked dopamine release in the nucleus accumbens of rats performing cost-benefit decision-making paradigms to evaluate critically the relationship between dopamine-associated cached values and preferences. By manipulating the amount of effort required to obtain rewards of different sizes, we were able to bias rats toward preferring an option yielding a high-value reward in some sessions and toward instead preferring an option yielding a low-value reward in others. Therefore, this approach permitted the investigation of dopamine-associated cached values in a context in which reward magnitude and subjective preference were dissociated. We observed greater cue-evoked mesolimbic dopamine release to options yielding the high-value reward even when rats preferred the option yielding the low-value reward. This result identifies a clear mismatch between the ordinal utility of the available options and the rank ordering of their cached values, thereby providing robust evidence that dopamine-associated cached values cannot be the sole determinant of choices in simple economic decision making.
Databáze:	MEDLINE
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