| Differential influence of levodopa on reward-based learning in Parkinson's disease. | |
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MedLine Citation:
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PMID: 21048900 Owner: NLM Status: PubMed-not-MEDLINE |
Abstract/OtherAbstract:
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The mesocorticolimbic dopamine (DA) system linking the dopaminergic midbrain to the prefrontal cortex and subcortical striatum has been shown to be sensitive to reinforcement in animals and humans. Within this system, coexistent segregated striato-frontal circuits have been linked to different functions. In the present study, we tested patients with Parkinson's disease (PD), a neurodegenerative disorder characterized by dopaminergic cell loss, on two reward-based learning tasks assumed to differentially involve dorsal and ventral striato-frontal circuits. 15 non-depressed and non-demented PD patients on levodopa monotherapy were tested both on and off medication. Levodopa had beneficial effects on the performance on an instrumental learning task with constant stimulus-reward associations, hypothesized to rely on dorsal striato-frontal circuits. In contrast, performance on a reversal learning task with changing reward contingencies, relying on ventral striato-frontal structures, was better in the unmedicated state. These results are in line with the "overdose hypothesis" which assumes detrimental effects of dopaminergic medication on functions relying upon less affected regions in PD. This study demonstrates, in a within-subject design, a double dissociation of dopaminergic medication and performance on two reward-based learning tasks differing in regard to whether reward contingencies are constant or dynamic. There was no evidence for a dose effect of levodopa on reward-based behavior with the patients' actual levodopa dose being uncorrelated to their performance on the reward-based learning tasks. |
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Authors:
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Susanne Graef; Guido Biele; Lea K Krugel; Frank Marzinzik; Michael Wahl; Johann Wotka; Fabian Klostermann; Hauke R Heekeren |
Publication Detail:
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Type: Journal Article Date: 2010-10-14 |
Journal Detail:
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Title: Frontiers in human neuroscience Volume: 4 ISSN: 1662-5161 ISO Abbreviation: Front Hum Neurosci Publication Date: 2010 |
Date Detail:
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Created Date: 2010-11-04 Completed Date: 2011-07-14 Revised Date: 2013-05-29 |
Medline Journal Info:
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Nlm Unique ID: 101477954 Medline TA: Front Hum Neurosci Country: Switzerland |
Other Details:
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Languages: eng Pagination: 169 Citation Subset: - |
Affiliation:
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Max Planck Institute for Human Development Berlin, Germany. |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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