Shiner, T and Seymour, B and Wunderlich, K and Hill, C and Bhatia, KP and Dayan, P and Dolan, RJ (2012) Dopamine and performance in a reinforcement learning task: evidence from Parkinson's disease. Brain, 135. pp. 1871-1883.Full text not available from this repository.
The role dopamine plays in decision-making has important theoretical, empirical and clinical implications. Here, we examined its precise contribution by exploiting the lesion deficit model afforded by Parkinson's disease. We studied patients in a two-stage reinforcement learning task, while they were ON and OFF dopamine replacement medication. Contrary to expectation, we found that dopaminergic drug state (ON or OFF) did not impact learning. Instead, the critical factor was drug state during the performance phase, with patients ON medication choosing correctly significantly more frequently than those OFF medication. This effect was independent of drug state during initial learning and appears to reflect a facilitation of generalization for learnt information. This inference is bolstered by our observation that neural activity in nucleus accumbens and ventromedial prefrontal cortex, measured during simultaneously acquired functional magnetic resonance imaging, represented learnt stimulus values during performance. This effect was expressed solely during the ON state with activity in these regions correlating with better performance. Our data indicate that dopamine modulation of nucleus accumbens and ventromedial prefrontal cortex exerts a specific effect on choice behaviour distinct from pure learning. The findings are in keeping with the substantial other evidence that certain aspects of learning are unaffected by dopamine lesions or depletion, and that dopamine plays a key role in performance that may be distinct from its role in learning.
|Uncontrolled Keywords:||Adult Aged Aged, 80 and over Association Learning Carbidopa Choice Behavior Dopamine Agents Dose-Response Relationship, Drug Drug Combinations Female Generalization (Psychology) Humans Image Processing, Computer-Assisted Levodopa Magnetic Resonance Imaging Male Middle Aged Nucleus Accumbens Oxygen Parkinson Disease Photic Stimulation Prefrontal Cortex Psychomotor Performance Reinforcement (Psychology)|
|Divisions:||Div F > Computational and Biological Learning|
|Depositing User:||Cron Job|
|Date Deposited:||07 Mar 2014 11:22|
|Last Modified:||08 Sep 2014 01:08|
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