Specific areas of the brain impaired by years of heavy drinking have been identified in young adult women by researchers at the University of California, San Diego (UCSD) School of Medicine and the Veterans Affairs Health Care System, San Diego. Previously, investigators have relied on thinking and memory tests to gauge brain dysfunction in alcoholics, but no one had identified the actual brain sites where impairment occurs in young adults.
Published in the February issue of Alcoholism: Clinical & Experimental Research, the study utilized sophisticated brain scans called functional magnetic resonance imaging (fMRI). The research was headed by Susan F. Tapert, Ph.D., UCSD assistant adjunct professor of psychiatry and a clinical psychologist at the Veterans Affairs Health Care System, who notes that “our findings suggest that even young and physically healthy individuals risk damaging their brains through chronic, heavy use of alcohol.” Tapert's team included Sandra A. Brown, Ph.D., and Gregory G. Brown, Ph.D., both of UCSD and the Veterans Affairs Health Care System, San Diego.
Tapert notes that characterizing specific areas of brain dysfunction caused by heavy drinking is critical to understanding how and when early alcoholism leads to brain impairment. She adds that her team is conducting further research with teenage boys and girls to determine which brain regions are affected early in the clinical course of alcoholism.
In the published work, Tapert and her team recruited and tested young women 18- to 25-years-old with a history of alcohol abuse since adolescence, and a group of same-age women with no history of heavy drinking. Both groups of women had abstained from alcohol for the previous 72 hours. As the women performed a nonverbal working memory test, the researchers found the alcoholic women had significant abnormalities, especially on the brain’s right side, and in the frontal lobe and parietal lobe, which is located in the upper back portion of the brain. These are areas of the brain previously identified as active when normal individuals perform spatial tasks such as reading maps, doing puzzles or mentally calculating math problems.
To determine the specific brain sites impacted in the women, the researchers utilized fMRI, which works by measuring changes in blood oxygen levels during neural activity, such as performing cognitive and memory tasks. In a clinical setting, conventional MRI is a noninvasive tool that provides detailed pictures of the anatomy of the brain. fMRI expands on this imaging capability by taking pictures of the brain every few seconds, so that researchers can paste together what Tapert calls a “movie” of activity in the brain while the subject is doing a mental task.
The UCSD/VA researchers did not observe structural abnormalities in the brains of the young alcoholic women in contrast to studies of older alcoholics. Rather, they witnessed changes in blood and oxygen use in the brain as the women performed memory tasks.
“Areas of the brain that are active with specific tasks need oxygenated blood to nourish the active areas,” Tapert says. “During memory tasks, the women with a drinking history had less oxygenated blood in the frontal and parietal lobes of the brain. These are areas needed for a variety of everyday tasks, such as finding our way around or handling all the information that bombards us on a daily basis.”
|This shows a 20-year old female nondrinkers response to the spatial working memory task. Brain activation is shown in bright colors.||This shows an alcohol-dependent 20-year old female's response to the spatial working memory task. Brain activation is shown in bright colors.|
In addition to identifying the specific sites of brain dysfunction, the researchers noted that women with a history of more severe withdrawal symptoms performed more poorly on the memory tasks.
“As these results point to withdrawal symptoms as a correlate of diminished brain response and performance, prevention programs may do well to target heavy drinking patterns that are followed by post-drinking effects,” the researchers say in their paper.
Tapert’s team plans additional research to determine if the brain dysfunction noted in the young women is permanent or if it might improve with abstinence. However, she notes that three of the 10 alcoholic women in the study had been sober for at least six months prior to the testing, yet exhibited the same functional impairment as the women still drinking.
|The left image is an averaged image of 10 nondrinker/social drinker young women, and the right is an averaged image of the 10 alcohol-dependent young women. Red, orange, and yellow show where the brain was active during spatial working memory, with yellow indicating the highest level of activity. Notice that there is less yellow in the back (bottom of the picture) right of the alcohol-dependent women's fMRI.|
Women were selected for the study so that male vs. female brain physiology would not impact the results. In addition, previous research had suggested that women might be as sensitive to the adverse effects of alcohol as men, even though they had been drinking for a shorter period.
In addition to Tapert, the paper’s authors were Gregory G. Brown, Ph.D.; Sandra
S. Kindermann, Ph.D.; Erick H. Cheung, B.S.; Lawrence R. Frank, Ph.D.; and
Sandra A. Brown, Ph.D. The study was funded by the National Institute on Alcohol Abuse and
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