As recovering spring breakers are regretting binge drinking escapades, it may be hard for them to appreciate that there is a positive side to the nausea, sleepiness, and stumbling. University of Utah neuroscientists report that when a region of the brain called the lateral habenula is chronically inactivated in rats, they repeatedly drink to excess and are less able to learn from the experience. The study, published online in the open-access journal PLOS ONE on April 2, 2014, has implications for understanding behaviors that drive alcohol addiction. While complex societal pressures contribute to alcoholism, physiological factors are also to blame. Alcohol is a drug of abuse, earning its status because it tickles the reward system in the brain, triggering the release of feel-good neurotransmitters. The dreaded outcomes of overindulging serve the beneficial purpose of countering the pull of temptation, but little is understood about how those mechanisms are controlled. University of Utah professor of neurobiology and anatomy Sharif Taha, Ph.D. and colleagues, tipped the balance that reigns in addictive behaviors by inactivating in rats the lateral habenula. When these rats were given intermittent access to a solution of 20% alcohol over several weeks, they escalated their alcohol drinking more rapidly, and drank more heavily than control rats. "In people, escalation of intake is what eventually separates a social drinker from someone who becomes an alcoholic," said Dr. Taha. "These rats drink amounts that are quite substantial. Legally they would be drunk if they were driving." The lateral habenula is activated by bad experiences, suggesting that without this region the rats may drink more because they fail to learn from the negative outcomes of overindulging.
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