The Durk Pearson & Sandy Shaw®
Life Extension NewsTM
Volume 19 No. 3 • April 2016


RISKY CHOICES AND DRD2

That the DRD2 dopamine receptor gene is a causative factor in risky decisionmaking is, we believe, becoming well supported, based on experimental evidence both in humans and that of animals. (Zalocusky, 2016). There is also mounting evidence of its involvement in addictions. Addiction appears to result when the brain’s cost-benefit analysis incorrectly causes individuals to choose risky behaviors such as those associated with addictive behaviors (e.g., excessive eating, compulsive sexual behavior, drug abuse, or gambling). The downgrading of the risks of an action while continuing to value its benefits can lead to highly maladaptive choices.

A recent study (Nasrallah, 2011) described the effects of alcohol use in adolescent rats, showing that subsequently the rats made more risky decisions. The researchers exposed adolescent rats to alcohol to assess its effects on risk-based decisions in the mesolimbic dopamine system, “the site of action for virtually all abused substances.” What they found was that “a history of adolescent alcohol use alters dopamine signaling to risk but not to reward.” “... the maladaptive bias toward large but risky outcomes displayed by these rats suggests that they overvalue larger rewards and/or fail to appropriately discount that value based on its diminished probability of occurrence.” “A corruption of reward valuation could promote maladaptive and suboptimal behavior by placing excessive priority on seeking rewards such as food, drugs, or sex.”

As reported in a later study, “...risk preferring rats could be instantaneously converted to risk-averse rats with precisely timed phasic stimulation of NAc [nucleus accumbens] D2R [DRD2] cells.” (Zalocusky, 2016) The implication is that stimulation of the DRD2 dopamine receptors would increase dopamine activity via these receptors and counteract the negative effect of (in this case) alcohol and possibly other forms of addiction (which are known to be associated with decreased DRD2 activity).

As noted in Reuter, 2006, “[g]eneral cognitive ability (intelligence, often indexed by IQ scores) is one of the most highly heritable behavioral phenotypes.” It has slowly come to be the general view among scientists that IQ does provide a rough measure of intelligence.” Creativity is not the same as intelligence, however, and heredity may, on the basis of twin studies, contribute perhaps 20% of the genetic contribution. This is controversial due to difficulties in measuring creativity. In the case of numerical creativity, there was a modest correlation with intelligence.

References

  • Reuter et al. Identification of first candidate genes for creativity: a pilot study. Brain Res. 1069:190-7 (2006).
  • Nasrallah et al. Risk preference following adolescent alcohol use is associated with corrupted encoding of costs but not rewards by mesolimbic dopamine. Proc Natl Acad Sci U S A. 108(13):5466-71 (2011).
  • Zalocusky, “Nucleus accumbens D2R cells signal prior outcomes and control risky decision-making. Nature. doi:10.1038/nature17400 (2016).

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