Long-Term Effects of Binge-Like Alcohol Consumption during Adolescence

Binge-like exposure to alcohol during adolescence can lead to deficits in executive function and changes in behavioral control in adulthood, according to a recent study in animals. A team of scientists supported by NIAAA and led by researchers at the Medical University of South Carolina in Charleston, exposed adolescent rats to repeated cycles of alcohol vapor to simulate binge alcohol intoxication. After the animals reached adulthood, the scientists tested them in a series of tasks measuring learning ability and other functions controlled by the brain’s prefrontal cortex (PFC). The investigators also conducted brain scans to look for changes in various regions in the brain. The results from these rats were compared with results from a control group of rats that had not been exposed to alcohol in adolescence.

The researchers found that, compared with the control animals, the alcohol-exposed animals showed decreased behavioral flexibility when learning new cognitive tasks and were less inhibited when performing a maze test. The adult animals that had been exposed to alcohol were also more resistant than the control group to training designed to inhibit response to alcohol cues. Importantly, the authors found that these behavioral deficits were reversed when the alcohol-exposed animals were given a compound that improves the function of glutamate receptors in the brain.

Brain scans of the adult rats revealed that the volumes of the hippocampus, thalamus, dorsal striatum, and neocortex were smaller, while the hypothalamus was larger in the alcohol-exposed group compared with controls. These brain regions have been implicated in various aspects of cognition and addiction.

Source:

Gass, J.T.; Glen, W.B., Jr.; McGonigal, J.T.; et al. Adolescent alcohol exposure reduces behavioral flexibility, promotes disinhibition, and increases resistance to extinction of ethanol self-administration in adulthood. Neuropsychopharmacology. October 2014, 39(11):2570–83.PMID: 24820536