Electroencephalographic and behavioral observations in rats during chronic ethanol ingestion and after abstinence

Increasing aqueous solutions of ethanol were given to rats, starting immediately after weaning, instead of drinking water. A 12% v/v concentration was reached on day 81 of age and maintained from then on. Animals drinking 12% ethanol had a median blood alcohol level of 333 mg/l. No major changes in their hippocampal or neocortical EEG patterns were observed at the age of 3 1/2 or 6--7 months while they were on the drug. Upon withdrawal, the younger group showed a decline of the mean frequency of hippocampal and neocortical large, irregular amplitude EEG activity; the older group showed instead a decline of the frequency of hippocampal theta. The performance of psuedoconditioned and of conditioned shuttle responses was unaltered after 3 1/2 to 6 months of ethanol consumption or after one week of abstinence from the drug.