People often take up drinking in order to overcome or forget a traumatic experience. However, excessive drinking can rewire the brain and the opposite effect is possible. According to a new research, people who drink excessively tend to linger with a trauma longer than sober people.
According to the researchers from National Institute on Alcohol Abuse and Alcoholism (NIAAA) and UNC's Bowles Center for Alcohol Studies, alcohol alters function in key area of brain that governs people's personality. The research could help in learning about alcoholism and post-traumatic stress disorder.
In the study, researchers taught sets of mice to fear a particular sound. They achieved this by giving an electric shock to the mice whenever the sound was played. One set of the mice was given twice the legal amount of alcohol while the other set wasn't given any alcohol.
During the course of experiment, researchers stopped giving electric shocks to the mice along with the tone. Gradually mice that weren't given any alcohol got used to the tone and learnt that it wasn't dangerous any more. However, the mice that were on alcohol, reacted with fear (freezing in a position) every time they heard the sound, even when it was no longer accompanied by a shock.
"There's a whole spectrum to how people react to a traumatic event. It's the recovery that we're looking at-the ability to say 'this is not dangerous anymore.' Basically, our research shows that chronic exposure to alcohol can cause a deficit with regard to how our cognitive brain centers control our emotional brain centers," said one of the authors of the study, Thomas Kash, PhD, assistant professor of pharmacology at the University of North Carolina School of Medicine.
Researchers compared the brains of mice that were on alcohol to brains of normal mice. They found significant differences in the brain structure, especially in the pre-frontal cortex- the region associated with cognitive function, social behavior, decision making and modulation of intense behavior. Researchers found that the nerve cells in this region of the brain were shaped differently.
A key receptor known as NMDA (N-methyl-D-aspartate) was also suppressed in the mice that had large doses of alcohol. The function at this particular receptor is associated with all the signs of alcoholism like dependence, craving and withdrawal.
"We're not only seeing that alcohol has detrimental effects on a clinically important emotional process, but we're able to offer some insight into how alcohol might do so by disrupting the functioning of some very specific brain circuits," said NIAAA scientist Andrew Holmes, PhD, the study's senior author.
"This study is exciting because it gives us a specific molecule to look at in a specific brain region, thus opening the door to discovering new methods to treat these disorders," said Kash.
The study is published in the journal Nature Neuroscience.