Pikas survive harsh winters by reducing their metabolism to conserve energy and by eating yak feces.
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Edited by Floyd Bloom, The Scripps Research Institute, La Jolla, CA, and approved January 11, 2010 (received for review October 25, 2009)
Abstract
Sensation seeking is a core personality trait that declines with age in both men and women, as do also both density and availability of the dopamine D2/3 receptors in striatum and cortical regions. In contrast, novelty seeking at a given age relates inversely to dopamine receptor availability. The simplest explanation of these findings is an inverted-U-shaped correlation between ratings of sensation seeking on the Zuckerman scale and dopamine D2/3 receptor availability. To test the claim of an inverted-U-shaped relation between ratings of the sensation-seeking personality and measures of dopamine receptor availability, we used PET to record [11C]raclopride binding in striatum of 18 healthy men. Here we report that an inverted-U shape significantly matched the receptor availability as a function of the Zuckerman score, with maximum binding potentials observed in the midrange of the scale. The inverted-U shape is consistent with a negative correlation between sensation seeking and the reactivity (“gain”) of dopaminergic neurotransmission to dopamine. The correlation reflects Zuckerman scores that are linearly linked to dopamine receptor densities in the striatum but nonlinearly linked to dopamine concentrations. Higher dopamine occupancy and dopamine concentrations explain the motivation that drives afflicted individuals to seek sensations, in agreement with reduced protection against addictive behavior that is characteristic of individuals with low binding potentials.
Footnotes
- 1To whom correspondence should be addressed. E-mail: gjedde{at}sund.ku.dk.
Author contributions: A.G., J.L., and P.C. designed research; A.M. performed research; A.G., Y.K., P.C., and J.L. analyzed data; and A.G., P.C., and J.L. wrote the paper.
The authors declare no conflict of interest.
This article is a PNAS Direct Submission.
This article contains supporting information online at www.pnas.org/cgi/content/full/0912319107/DCSupplemental.
Inverted-U-shaped correlation between dopamine receptor availability in striatum and sensation seeking
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