*The following is excerpted from an online article from EurekAlert!
Binge drinking can have lasting effects on brain pathways that are still developing during adolescence, say neuroscience researcher Heather N. Richardson and her colleagues at the University of Massachusetts Amherst and Louisiana State University. Results of their study using a rodent model of adolescent drinking appear in the October 29 issue of The Journal of Neuroscience.
Richardson says, "Adverse effects of this physical damage can persist long after adolescent drinking ends. We found that the effects of alcohol are enduring." She adds, "The brains of adolescent rats appear to be sensitive to episodic alcohol exposure. These early experiences with alcohol can physically alter brain structure, which may ultimately lead to impairments in brain function in adulthood."
She and her colleagues believe their study is the first to show that voluntary alcohol drinking has these effects on the physical development of neural pathways in the prefrontal cortex, one of the last brain regions to mature.
In humans, early onset of alcohol use in young teenagers has been linked to memory problems, impulsivity and an increased risk of alcoholism in adulthood. Because adolescence is a period when the prefrontal cortex matures, Richardson adds, it is possible that alcohol exposure might alter the course of brain development. Rodent models used in this study are documented to have clinical relevance to alcohol use disorder in humans
The prefrontal cortex is the center of decision-making and regulates emotions and impulses. Specifically, the researchers explored the physical damage to fatty myelin sheaths that wrap and insulate axons, the "wires" that transmit information from one neuron to another. Myelin increases the speed at which electrical impulses travel along axons, enhancing information-processing and cognitive performance.
The researchers examined myelin at the end of the binge-drinking period and found that it was reduced in the prefrontal cortex of the binge drinking adolescent rats. In a separate experiment, they examined myelin several months later after testing for adult drinking behaviors and found that adolescent alcohol drinking caused significant white matter loss and damage to myelin in the prefrontal cortex.
In a final experiment, the researchers found that heavy adolescent alcohol drinking, but not sweetened water, predicted poor performance on a working memory task in adulthood. This supports the idea that the enduring effects of alcohol may not only be structural but could also affect cognitive functions that are dependent on a healthy prefrontal cortex.