2013年9月5日木曜日

Dopamine Modulates Risk-Taking as a Function of Baseline Sensation-Seeking Trait

Agnes Norbury, Sanjay Manohar, Robert D. Rogers, and Masud Husain
J. Neurosci. 2013;33 12982-12986 Open Access
http://www.jneurosci.org/cgi/content/abstract/33/32/12982?etoc

ドーパミンとリスク選好の関係。
D2/D3 agonistを用いて「ドーパミンD2/D3レセプターの感受性を高める」と、ヒトは「リスク愛好的」になる。
また、この効果は「元々リスク回避的なヒト」で顕著であった。

Trait sensation-seeking, defined as a need for varied, complex, and intense sensations, represents a relatively underexplored hedonic drive in human behavioral neuroscience research. It is related to increased risk for a range of behaviors including substance use, gambling, and risky sexual practice. Individual differences in self-reported sensation-seeking have been linked to brain dopamine function, particularly at D2-like receptors, but so far no causal evidence exists for a role of dopamine in sensation-seeking behavior in humans. Here, we investigated the effects of the selective D2/D3 agonist cabergoline on performance of a probabilistic risky choice task in healthy humans using a sensitive within-subject, placebo-controlled design. Cabergoline significantly influenced the way participants combined different explicit signals regarding probability and loss when choosing between response options associated with uncertain outcomes. Importantly, these effects were strongly dependent on baseline sensation-seeking score. Overall, cabergoline increased sensitivity of choice to information about probability of winning; while decreasing discrimination according to magnitude of potential losses associated with different options. The largest effects of the drug were observed in participants with lower sensation-seeking scores. These findings provide evidence that risk-taking behavior in humans can be directly manipulated by a dopaminergic drug, but that the effectiveness of such a manipulation depends on baseline differences in sensation-seeking trait. This emphasizes the importance of considering individual differences when investigating manipulation of risky decision-making, and may have relevance for the development of pharmacotherapies for disorders involving excessive risk-taking in humans, such as pathological gambling.

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