Assaying the effect of levodopa on the evaluation of risk in healthy humans

In humans, dopamine is implicated in reward and risk-based decision-making. However, the specific effects of dopamine augmentation on risk evaluation are unclear. Here we sought to measure the effect of 100 mg oral levodopa, which enhances synaptic release of dopamine, on choice behaviour in healthy...

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Main Authors: Symmonds, M, Wright, N, Fagan, E, Dolan, R
Format: Journal article
Language:English
Published: Public Library of Science 2013
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author Symmonds, M
Wright, N
Fagan, E
Dolan, R
author_facet Symmonds, M
Wright, N
Fagan, E
Dolan, R
author_sort Symmonds, M
collection OXFORD
description In humans, dopamine is implicated in reward and risk-based decision-making. However, the specific effects of dopamine augmentation on risk evaluation are unclear. Here we sought to measure the effect of 100 mg oral levodopa, which enhances synaptic release of dopamine, on choice behaviour in healthy humans. We use a paradigm without feedback or learning, which solely isolates effects on risk evaluation. We present two studies (n = 20; n = 20) employing a randomised, placebo-controlled, within-subjects design. We manipulated different dimensions of risk in a controlled economic paradigm. We test effects on risk-reward tradeoffs, assaying both aversion to variance (the spread of possible outcomes) and preference for relative losses and gains (asymmetry of outcomes - skewness), dissociating this from potential non-specific effects on choice randomness using behavioural modelling. There were no systematic effects of levodopa on risk attitudes, either for variance or skewness. However, there was a drift towards more risk-averse behaviour over time, indicating that this paradigm was sensitive to detect changes in risk-preferences. These findings suggest that levodopa administration does not change the evaluation of risk. One possible reason is that dopaminergic influences on decision making may be due to changing the response to reward feedback.
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spelling oxford-uuid:04f551e7-2a73-4383-b82c-d7979dc0a21d2022-03-26T08:54:35ZAssaying the effect of levodopa on the evaluation of risk in healthy humansJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:04f551e7-2a73-4383-b82c-d7979dc0a21dEnglishSymplectic Elements at OxfordPublic Library of Science2013Symmonds, MWright, NFagan, EDolan, RIn humans, dopamine is implicated in reward and risk-based decision-making. However, the specific effects of dopamine augmentation on risk evaluation are unclear. Here we sought to measure the effect of 100 mg oral levodopa, which enhances synaptic release of dopamine, on choice behaviour in healthy humans. We use a paradigm without feedback or learning, which solely isolates effects on risk evaluation. We present two studies (n = 20; n = 20) employing a randomised, placebo-controlled, within-subjects design. We manipulated different dimensions of risk in a controlled economic paradigm. We test effects on risk-reward tradeoffs, assaying both aversion to variance (the spread of possible outcomes) and preference for relative losses and gains (asymmetry of outcomes - skewness), dissociating this from potential non-specific effects on choice randomness using behavioural modelling. There were no systematic effects of levodopa on risk attitudes, either for variance or skewness. However, there was a drift towards more risk-averse behaviour over time, indicating that this paradigm was sensitive to detect changes in risk-preferences. These findings suggest that levodopa administration does not change the evaluation of risk. One possible reason is that dopaminergic influences on decision making may be due to changing the response to reward feedback.
spellingShingle Symmonds, M
Wright, N
Fagan, E
Dolan, R
Assaying the effect of levodopa on the evaluation of risk in healthy humans
title Assaying the effect of levodopa on the evaluation of risk in healthy humans
title_full Assaying the effect of levodopa on the evaluation of risk in healthy humans
title_fullStr Assaying the effect of levodopa on the evaluation of risk in healthy humans
title_full_unstemmed Assaying the effect of levodopa on the evaluation of risk in healthy humans
title_short Assaying the effect of levodopa on the evaluation of risk in healthy humans
title_sort assaying the effect of levodopa on the evaluation of risk in healthy humans
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