Impairments of brain and behavior: the neurological effects of alcohol

Abstract

Chronic heavy drinking and alcoholism can have serious repercussions for the functioning of the entire nervous system, particularly the brain. These effects include changes in emotions and personality as well as impaired perception, learning, and memory. Neuropathological and imaging techniques have provided evidence of physical brain abnormalities in alcoholics, such as atrophy of nerve cells and brain shrinkage. At the cellular level, alcohol appears to directly affect brain function in a variety of ways, primarily by interfering with the action of glutamate, gamma-aminobutyric acid, and other neurotransmitters. Neurological disorders also can result from vitamin deficiency and liver disease, two health problems that commonly occur with alcoholism. Other hypotheses, based on factors such as aging, gender, and genetics, have been developed to explain various alcohol-related neurological consequences. Many pharmacological treatments to improve neuropsychological functioning in alcoholics have been tested, but none has proved entirely successful. With prolonged abstinence, however, slow recovery of cognitive functioning can occur in some cases.

Figure 1

Sources of neurological complications of alcohol and alcoholism. SOURCE: Adapted from Bernat, J.L., and Victor, M. The Neurological Complications of Alcohol and Alcoholism. Unit 7. 2d ed. Developed by the Project Cork Institute at Dartmouth Medical School. Timonium, MD: Milner-Fenwick, 1994.

Figure 2

Schematic of a lengthwise cross-section through the human brain. Brain structures that most frequently have been implicated in alcohol-related neurological disorders include parts of the diencephalon (i.e., the mammillary bodies of the hypothalamus and the dorsomedial nucleus within the thalamus), the cerebral cortex, and several central neuro-transmitter (i.e.,nerve cell communication) systems.

Figure 3

Schematic of a cross-section through the human brain. Brain structures that have been implicated in alcohol-related neurological disorders include parts of the limbic system (i.e., the hippocampus and the amygdala), the mammillary bodies of the hypothalamus, and the dorsomedial nucleus within the thalamus. SOURCE: Adapted from Nieuwenhuys, R.; Voogd, J.; and van Huijzen, C. The Human Central Nervous System: A Synopsis and Atlas. New York: Springer Verlag, 1988.

Figure 4

Schematic representation of perceptual and language functions in the right and left cerebral hemispheres of the human brain.