Tuesday, July 20, 2010

Dopamine, Time, and Our Impulsivity

Yet another fascinating piece of work from the group around Ray Dolan at the London Wellcome Trust Center for Neuroimaging. They show that enhancing dopamine activity can increase our propensity to choose smaller–sooner over larger–later rewards:

Disordered dopamine neurotransmission is implicated in mediating impulsiveness across a range of behaviors and disorders including addiction, compulsive gambling, attention-deficit/hyperactivity disorder, and dopamine dysregulation syndrome. Whereas existing theories of dopamine function highlight mechanisms based on aberrant reward learning or behavioral disinhibition, they do not offer an adequate account of the pathological hypersensitivity to temporal delay that forms a crucial behavioral phenotype seen in these disorders. Here we provide evidence that a role for dopamine in controlling the relationship between the timing of future rewards and their subjective value can bridge this explanatory gap. Using an intertemporal choice task, we demonstrate that pharmacologically enhancing dopamine activity increases impulsivity by enhancing the diminutive influence of increasing delay on reward value (temporal discounting) and its corresponding neural representation in the striatum. This leads to a state of excessive discounting of temporally distant, relative to sooner, rewards. Thus our findings reveal a novel mechanism by which dopamine influences human decision-making that can account for behavioral aberrations associated with a hyperfunctioning dopamine system.

3 comments:

Mike Mike said...

Thanks for pointing this out! It's been thought for some time that impaired temporal discounting is one of the key deficits that develops in drug addiction, and this study apparently bolsters the plausibility of that hypothesis a bit.

Anonymous said...

However this may not just be a negative phenomena. Historically if you were a warrior and s bunch of guys started swinging swords at you...well now would not be a good time for reflection and consideration of the broader issues. Today, fast paced sports may benefit from this style of thinking. This leads to the question will athletes start enhancing their dopamine levels to decrease delays? If it leads to inhibition will actors use it gain access to more emotions?

Madelyn Griffith-Haynie said...

Nice! (I'm a big fan of SciAm and SciAm Mind,and I always love it when anything from the Wellcome Trust is featured).

FYI: I linked this article in the Related Content on "The Impulsivity RunDown™" on ADDandSoMuchMore - which briefly explains the difference in our brain's two response pathways - hop over and take a look.

~~~~~
Madelyn Griffith-Haynie, CMC, SCAC, MCC
- ADD Coach Training Field founder; ADD Coaching co-founder -
(blogs: ADDandSoMuchMore, ADDerWorld & ethosconsultancynz - dot com)
"It takes a village to educate a world!"

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