Electrophysiological changes after repeated alcohol withdrawal

Abstract

Studies of spontaneous and kindled electrophysiological brain activity following AW emphasize the important contribution of several variables to the severity of AW and to the associated long-lasting changes in brain function. Thus, withdrawal severity depends on the pattern of alcohol intake (e.g., withdrawal history) as well as on the total amount of alcohol exposure. Moreover, different brain regions respond differently to various patterns of alcohol exposure.

Figure 1

Sample electroencephalogram (EEG) recorded from a rat following alcohol withdrawal. Filled circles indicate computer-detected spikes and sharp waves, which are indicators of abnormal brain activity. Hipp = hippocampus. SOURCE: Adapted from Veatch and Gonzalez 1996.

Figure 2

Effects of multiple cycles of alcohol exposure and withdrawal on abnormal brain waves (i.e., spike and sharp wave [SSW] activity) of rats. Rats were exposed to alcohol vapors either for two cycles of 10 days of alcohol exposure followed by 4 days of withdrawal or for three cycles of 20 days of exposure followed by 4 days of withdrawal. After the first and last withdrawal episode in each group, the SSW activity in two regions (CA₁ and CA₃) of the hippocampus¹ was recorded by electroencephalogram (EEG) and averaged. SSW activity in the CA₁ area was most affected by increases in total alcohol exposure, whereas activity in the CA₃ area depended primarily on the number of withdrawal cycles. These results indicate that both total alcohol exposure and the number of withdrawal episodes influence electrophysiological activity during alcohol withdrawal. Moreover, different brain structures appear to be sensitive to different aspects of the alcohol exposure and withdrawal cycles. ¹ The hippocampus is a region of the brain thought to play a role in learning and memory as well as in alcohol withdrawal seizures. ^aStatistically significant (i.e., p < 0.05) compared with 10-day cycles, first withdrawal. ^bStatistically significant (i.e., p < 0.05) compared with 10-day cycles, last withdrawal. ^cStatistically significant (i.e., p < 0.05) compared with 20-day cycles, first withdrawal. SOURCE: Adapted from Veatch and Gonzalez 1996.