brain region

Mouse model links alcohol intake to marijuana-like brain compounds

Brain molecules similar to the active compound in marijuana help to regulate alcohol consumption, according to new reports by scientists. In studies conducted with a strain of mice known to have a high preference for alcohol, the scientists found greatly reduced alcohol intake in mice specially bred to lack CB1, the brain receptor for innate marijuana-like substances known as endocannabinoids. The effect was age dependent, the Bethesda group found. The New York scientists showed that the endocannabinoid system activates a brain region known as the nucleus accumbens, which plays a major role in mediating the rewarding effects of alcohol.

Addicts’ Brains Work Harder to Control Behavior

A brain-imaging study conducted at the U.S. Department of Energy’s Brookhaven National Laboratory reveals that recently abstinent methamphetamine abusers who reported they avoided harmful situations had higher resting metabolic rates in a part of the brain responsible for making decisions and modifying behaviors than those with low harm-avoidance scores. In non-addicted, comparison subjects, there was no significant association between harm avoidance and metabolism in this brain region. The findings, reported in the December 3, 2002, issue of NeuroReport, suggest that this higher-level brain center — the orbitofrontal cortex — is involved in drug addiction, and might be working extra hard in addicts trying to stay off drugs.

‘Sharp’ elders use left brain to compensate for aging right

Elderly adults who perform as well as younger adults on certain cognitive tests appear to enlist the otherwise underused left half of the prefrontal cortex of their brain in order to maintain performance, neuroscientists have found. In contrast, elderly people who are not “high performers” on the tests resemble younger adults in showing a preferred usage of the right side of the prefrontal cortex.