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Dopamine enhances expectation of pleasure in humans.

Sharot T, Shiner T, Brown AC, Fan J, Dolan RJ - Curr. Biol. (2009)

Bottom Line: Human action is strongly influenced by expectations of pleasure.Making decisions, ranging from which products to buy to which job offer to accept, requires an estimation of how good (or bad) the likely outcomes will make us feel [1].Here, we show that administration of a drug that enhances dopaminergic function (dihydroxy-L-phenylalanine; L-DOPA) during the imaginative construction of positive future life events subsequently enhances estimates of the hedonic pleasure to be derived from these same events.

View Article: PubMed Central - PubMed

Affiliation: Wellcome Trust Centre for Neuroimaging, University College London, London WC1N 3BG, UK. t.sharot@fil.ion.ucl.ac.uk

ABSTRACT
Human action is strongly influenced by expectations of pleasure. Making decisions, ranging from which products to buy to which job offer to accept, requires an estimation of how good (or bad) the likely outcomes will make us feel [1]. Yet, little is known about the biological basis of subjective estimations of future hedonic reactions. Here, we show that administration of a drug that enhances dopaminergic function (dihydroxy-L-phenylalanine; L-DOPA) during the imaginative construction of positive future life events subsequently enhances estimates of the hedonic pleasure to be derived from these same events. These findings provide the first direct evidence for the role of dopamine in the modulation of subjective hedonic expectations in humans.

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Experimental Task and Results(A) On day 1, participants rated stimuli before pharmacological manipulation (phase 1). They then completed an imagination task under placebo 1 (phase 2A) or L-DOPA (phase 2B; placebo 2 for order control group). On day 2, participants returned to the laboratory and completed a decision-making task (phase 3) and a final rating task (phase 4). For full details, see Supplemental Experimental Procedures.(B) Change in mean-corrected ratings from phase 1 to phase 4. Ratings of estimated happiness increased only for stimuli previously imagined under L-DOPA.(C) Difference scores (placebo 1 − L-DOPA; placebo 1 − placebo 2) for the change in mean-corrected ratings from phase 1 to phase 4. Ratings of estimated happiness increased from phase 1 to phase 4 for stimuli imagined under L-DOPA relative to placebo 1 only for selected stimuli. As expected, there was no difference in rating change for stimuli imagined under placebo 1 relative to placebo 2 in the control group for either selected stimuli or rejected stimuli.Error bars in (B) and (C) represent standard error of the mean. ∗p < 0.05.
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fig1: Experimental Task and Results(A) On day 1, participants rated stimuli before pharmacological manipulation (phase 1). They then completed an imagination task under placebo 1 (phase 2A) or L-DOPA (phase 2B; placebo 2 for order control group). On day 2, participants returned to the laboratory and completed a decision-making task (phase 3) and a final rating task (phase 4). For full details, see Supplemental Experimental Procedures.(B) Change in mean-corrected ratings from phase 1 to phase 4. Ratings of estimated happiness increased only for stimuli previously imagined under L-DOPA.(C) Difference scores (placebo 1 − L-DOPA; placebo 1 − placebo 2) for the change in mean-corrected ratings from phase 1 to phase 4. Ratings of estimated happiness increased from phase 1 to phase 4 for stimuli imagined under L-DOPA relative to placebo 1 only for selected stimuli. As expected, there was no difference in rating change for stimuli imagined under placebo 1 relative to placebo 2 in the control group for either selected stimuli or rejected stimuli.Error bars in (B) and (C) represent standard error of the mean. ∗p < 0.05.

Mentions: To test this, we measured people's estimated pleasure of future events both before and after imagining those events under the influence of L-DOPA. In addition, we introduced a decision-making task to examine how this process interacts with choice. We presented 61 healthy volunteers with 80 different vacation destinations (e.g., Greece, Thailand) and asked them to rate their expectations of happiness if they were to vacation at each of these locations (phase 1, rating 1; see Figure 1A). We then administered placebo 1 and asked the participants 40 min later to complete a subjective state questionnaire (e.g., level of alertness, calm, interest). Next, we re-presented half of the destinations and instructed participants to imagine themselves spending next year's vacation at those locations (Phase 2A, imagination under placebo 1). We then administered L-DOPA (100 mg) to 29 participants (“experimental group,” randomly assigned) and a second placebo pill to 32 participants (“order control group” controlling for possible order confound, because L-DOPA had to be administered after placebo in the experimental group because of its half-life, which results in it requiring upwards of 5 hr for elimination). Forty minutes later, all participants completed the subjective state questionnaire again. The other half of the stimulus set was then presented with the same instruction as per phase 2A (phase 2B, imagination under L-DOPA or placebo 2). Participants then left the laboratory and returned 24 hr later.


Dopamine enhances expectation of pleasure in humans.

Sharot T, Shiner T, Brown AC, Fan J, Dolan RJ - Curr. Biol. (2009)

Experimental Task and Results(A) On day 1, participants rated stimuli before pharmacological manipulation (phase 1). They then completed an imagination task under placebo 1 (phase 2A) or L-DOPA (phase 2B; placebo 2 for order control group). On day 2, participants returned to the laboratory and completed a decision-making task (phase 3) and a final rating task (phase 4). For full details, see Supplemental Experimental Procedures.(B) Change in mean-corrected ratings from phase 1 to phase 4. Ratings of estimated happiness increased only for stimuli previously imagined under L-DOPA.(C) Difference scores (placebo 1 − L-DOPA; placebo 1 − placebo 2) for the change in mean-corrected ratings from phase 1 to phase 4. Ratings of estimated happiness increased from phase 1 to phase 4 for stimuli imagined under L-DOPA relative to placebo 1 only for selected stimuli. As expected, there was no difference in rating change for stimuli imagined under placebo 1 relative to placebo 2 in the control group for either selected stimuli or rejected stimuli.Error bars in (B) and (C) represent standard error of the mean. ∗p < 0.05.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC2801060&req=5

fig1: Experimental Task and Results(A) On day 1, participants rated stimuli before pharmacological manipulation (phase 1). They then completed an imagination task under placebo 1 (phase 2A) or L-DOPA (phase 2B; placebo 2 for order control group). On day 2, participants returned to the laboratory and completed a decision-making task (phase 3) and a final rating task (phase 4). For full details, see Supplemental Experimental Procedures.(B) Change in mean-corrected ratings from phase 1 to phase 4. Ratings of estimated happiness increased only for stimuli previously imagined under L-DOPA.(C) Difference scores (placebo 1 − L-DOPA; placebo 1 − placebo 2) for the change in mean-corrected ratings from phase 1 to phase 4. Ratings of estimated happiness increased from phase 1 to phase 4 for stimuli imagined under L-DOPA relative to placebo 1 only for selected stimuli. As expected, there was no difference in rating change for stimuli imagined under placebo 1 relative to placebo 2 in the control group for either selected stimuli or rejected stimuli.Error bars in (B) and (C) represent standard error of the mean. ∗p < 0.05.
Mentions: To test this, we measured people's estimated pleasure of future events both before and after imagining those events under the influence of L-DOPA. In addition, we introduced a decision-making task to examine how this process interacts with choice. We presented 61 healthy volunteers with 80 different vacation destinations (e.g., Greece, Thailand) and asked them to rate their expectations of happiness if they were to vacation at each of these locations (phase 1, rating 1; see Figure 1A). We then administered placebo 1 and asked the participants 40 min later to complete a subjective state questionnaire (e.g., level of alertness, calm, interest). Next, we re-presented half of the destinations and instructed participants to imagine themselves spending next year's vacation at those locations (Phase 2A, imagination under placebo 1). We then administered L-DOPA (100 mg) to 29 participants (“experimental group,” randomly assigned) and a second placebo pill to 32 participants (“order control group” controlling for possible order confound, because L-DOPA had to be administered after placebo in the experimental group because of its half-life, which results in it requiring upwards of 5 hr for elimination). Forty minutes later, all participants completed the subjective state questionnaire again. The other half of the stimulus set was then presented with the same instruction as per phase 2A (phase 2B, imagination under L-DOPA or placebo 2). Participants then left the laboratory and returned 24 hr later.

Bottom Line: Human action is strongly influenced by expectations of pleasure.Making decisions, ranging from which products to buy to which job offer to accept, requires an estimation of how good (or bad) the likely outcomes will make us feel [1].Here, we show that administration of a drug that enhances dopaminergic function (dihydroxy-L-phenylalanine; L-DOPA) during the imaginative construction of positive future life events subsequently enhances estimates of the hedonic pleasure to be derived from these same events.

View Article: PubMed Central - PubMed

Affiliation: Wellcome Trust Centre for Neuroimaging, University College London, London WC1N 3BG, UK. t.sharot@fil.ion.ucl.ac.uk

ABSTRACT
Human action is strongly influenced by expectations of pleasure. Making decisions, ranging from which products to buy to which job offer to accept, requires an estimation of how good (or bad) the likely outcomes will make us feel [1]. Yet, little is known about the biological basis of subjective estimations of future hedonic reactions. Here, we show that administration of a drug that enhances dopaminergic function (dihydroxy-L-phenylalanine; L-DOPA) during the imaginative construction of positive future life events subsequently enhances estimates of the hedonic pleasure to be derived from these same events. These findings provide the first direct evidence for the role of dopamine in the modulation of subjective hedonic expectations in humans.

Show MeSH
Related in: MedlinePlus