Cradle of craving for booze in brain revealed
Neuroscientists have found the part of brain that controls sensitivity to the negative effects of drinking alcohol.
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.
U of U professor of neurobiology and anatomy Sharif Taha, Ph.D. and colleagues, tipped the balance that reigns in addictive behaviors by inactivating in rats a brain region called the lateral habenula. When the rats were given intermittent access to a solution of 20 per cent alcohol over several weeks, they escalated their alcohol drinking more rapidly, and drank more heavily than control rats.
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. The investigators tested the idea by giving the rats a desirable, sweet juice then injecting them with a dose of alcohol large enough to cause negative effects.
Yet rats with an inactivated lateral habenula sought out the juice more than control animals, even though it meant a repeat of the bad experience.
The researchers think the lateral habenula likely works in one of two ways. The region may regulate how badly an individual feels after over-drinking. Alternatively, it may control how well an individual learns from their bad experience. Future work will resolve between the two.
The study has been published online in PLOS ONE.
(Posted on 03-04-2014)