Briefly Noted

Compared to light drinkers, heavy drinkers have brains that have less energy due to decreases in glucose metabolism, researchers at the National Institutes of Health have found. In a study published online last week in Nature Communications , the researchers combined measures of the left brain (activity) and the right brain (glucose consumption) to better understand the effects of alcohol on people. “The brain uses a lot of energy compared to other body organs, and the association between brain activity and energy utilization is an important marker of brain health,” said George F. Koob, Ph.D., director of the National Institute on Alcohol Abuse and Alcoholism (NIAAA), in a statement accompanying the release of the results. “This study introduces a new way of characterizing how brain activity is related to its consumption of glucose, which could be very useful in understanding how the brain uses energy in health and disease.” The research was led by Ehsan Shokri‐Kojori, Ph.D., and Nora D. Volkow, M.D., both of the NIAAA Laboratory of Neuroimaging. Volkow is also the director of the National Institute on Drug Abuse. “The findings from this study highlight the relevance of energetics for ensuring normal brain function and reveal how it is disrupted by excessive alcohol consumption,” said Volkow. “We measured power by observing to what extent brain regions are active and use energy,” explained Shokri‐Kojori. “We measured cost of brain regions by observing to what extent their energy use exceeds their underlying activity.” Using a group of healthy volunteers, researchers showed that different brain regions have different power and cost. They then looked at the effects of alcohol on these measures by assessing a group that included light and heavy drinkers, and found that both acute and chronic use affected brain power and cost. “In heavy drinkers, we saw less regional power, for example, in the thalamus, the sensory gateway and frontal cortex of the brain, which is important for decision‐making,” said Shokri‐Kojori. “These decreases in power were interpreted to reflect toxic effects of long‐term exposure to alcohol on the brain cells.” There was also a disruption of visual processing during acute alcohol exposure, and significant decreases in cost of activity during alcohol intoxication.