November 17, 2011

Study finds alcoholics’ brains work harder to finish tasks

Study finds alcoholics’ brains work harder to finish tasks

Alcoholic brains can perform a simple finger-tapping exercise as well as their sober counterparts but they are working a lot harder to do it, according to a Vanderbilt study published in the journal Alcoholism: Clinical & Experimental Research.

The new study, using functional magnetic resonance imaging (fMRI) during a finger-tapping exercise, found a weakened relationship between frontal lobe and cerebellar activity in alcoholic individuals.

Baxter Rogers, Ph.D.

Baxter Rogers, Ph.D.

“The relationship was weaker in alcoholic people, even a week after they had stopped drinking,” said lead author Baxter Rogers, Ph.D., research assistant professor of Radiology and Radiological Sciences.

Chronic drinking is associated with neurocognitive deficits due to neuropathological changes in the structure, metabolism and function of the brain. One of the consequences of these deficits is impairment of motor functioning.

Rogers and colleagues used fMRI to examine 10 uncomplicated chronic alcoholic patients after five to seven days of abstinence, and once signs of withdrawal were no longer present, as well as 10 matched healthy controls.

Finger tapping involves portions of both the cerebellum and frontal cortex, Rogers said, and previous research strongly suggested that both are affected in alcoholism, especially the cerebellum.

“We used fMRI because it measures the function of the entire brain painlessly and non-invasively,” Rogers said. “And it can identify specific brain regions that are involved in tasks and that are affected in disease.”

The study showed that alcoholic patients could produce the same number of finger taps per minute as did the normal controls, but employed different parts of the brain to do it.

“This suggests that alcoholics needed to compensate for their brain injury,” he said. “They may need to expend more effort, or at least a different brain response, to produce a normal outcome on simple tasks because they are unable to utilize the brain regions needed in an integrated fashion.”

Rogers said that while the study was small, it supports other research showing problems in the frontal-cerebellar brain circuits in alcoholic patients. "Its major contribution is related to studying the simple tasks that alcoholics apparently perform quite normally," he said.

“Studies like this allow us to see what changes in brain strategies are employed by alcoholic patients in task performance, something that is not apparent to an examining physician without fMRI. Better understanding how brain circuits of alcoholics are rewired due to their disease may one day lead to new approaches to healing alcoholism and rehabilitation of these brain dysfunctions,” said Peter Martin, M.D., professor of Psychiatry and Pharmacology and senior author of the study

Results will be published in the February 2012 issue of Alcoholism: Clinical & Experimental Research and are currently available at Early View.