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Researchers studying the effects of alcohol use on the brain are aided by advanced technology such as magnetic resonance imaging (MRI), diffusion tensor imaging (DTI), positron emission tomography (PET), and electrophysiological brain mapping. These tools are providing valuable insight into how alcohol affects the brains structure and function.

Long term heavy drinking may lead to shrinking of the brain and deficiencies in the fibers (white matter) that carry information between brain cells (gray matter). MRI and DTI are being used together to assess the brains of patients when they first stop chronic heavy drinking and again after long periods of sobriety, to monitor for possible relapse to drinking.

Memory formation and retrieval are highly influenced by factors such as attention and motivation. Studies using MRI are helping scientists to determine how memory and attention improve with long-time abstinence from alcohol, as well as what changes take place when a patient begins drinking again. The goal of these studies is to determine which alcohol induced effects on the brain are permanent and which ones can be reversed with abstinence.

PET imaging is allowing researchers to visualize, in the living brain, the damage that results from heavy alcohol consumption. This snapshot of the brains function enables scientists to analyze alcohols effects on various nerve cell communication systems (i.e., neurotransmitter systems) as well as on brain cell metabolism and blood flow within the brain. These studies have detected deficits in alcoholics, particularly in the frontal lobes, which are responsible for numerous functions associated with learning and memory, as well as in the cerebellum, which controls movement and coordination. PET also is a promising tool for monitoring the effects of alcoholism treatment and abstinence on damaged portions of the brain and may help in developing new medications to correct the chemical deficits found in the brains of people with alcohol dependence.

Another high tech tool, electroencephalography (EEG), records the brains electrical signals. Small electrodes are placed on the scalp to detect this electrical activity, which then is magnified and graphed as brain waves (i.e., neural oscillations). These brain waves show real time activity as it happens in the brain.

Many male alcoholics have a distinctive electrophysiological profile that is, a low amplitude of their P3 components. P3 amplitudes in women alcoholics also are reduced, although to a lesser extent than in men. For many years it was assumed that the P3 deficit observed in alcoholics was the result of alcohols damage to the brain. Then it was determined that while many of the clinical symptoms and electrophysiological measures associated with alcoholism return to normal after abstinence, the P3 amplitude abnormality persists.

This continued deficit in long term abstinent alcoholics suggests that P3 deficits may be a marker of risk for alcohol dependence, rather than a result of alcohol use. In fact, a number of studies have since reported low P3 amplitudes in young people who have not started drinking alcohol but who are at high risk for developing alcoholism, such as young sons of alcoholic fathers. Markers such as the P3 can help identify people who may be at greatest risk for developing problems with alcohol.

For more information: niaaa.nih.gov