Synchronization of EEG activity of male rhesus monkeys Macaca mulatta treated with ovocyclin

Abstract

Bipolar stainless steel electrodes were stereotaxically implanted in hypothalamus and cortex of six male monkeys. The effect of intramuscular injection of estradiol dipropionate (ovocyclin) in a dose of 10 mg/d was observed on EEG activity on 3 successive days. On the first day, slow waves appeared only in preoptic and on the second day also in posterior hypothalamus. Generalized slowing with an increase in amplitude appeared in all the hypothalamic areas and cortex on the third day. This suggest estrogen to possess (i) cumulative effect on brain and (ii) inhibitory action in the form of synchronization of EEG activity.