In an animal study conducted by the Society for Neuroscience, which was published in The Journal of Neuroscience on October 29, researchers provided a test group of adolescent rats with daily doses of alcohol. These rats were found to have displayed significantly lower levels of myelin in their prefrontal cortexes than did other rats that were given sweetened water. The shortage of myelin, a fatty coating on nerve fibers responsible for the transmission of electrical signals between neurons, was correlated with lower performance scores on memory tests. This trend was observed even after the rats reached adulthood and were no longer given alcohol. The study thereby suggests that early exposure to alcohol exerts permanent damage on selective fibers in the brain that are vital to reasoning and memory.