Electroencephalographic responses produced by genital stimulation and hormone administration in sexually immature rhesus monkeys

Abstract

EEG activity from different hypothalamic, limbic and some other brain regions was recorded in unanaesthetised sexually immature male and female monkeys, through chronically implanted electrodes. On genital stimulation no specific changes in EEG responses were produced except a generalised arousal. Daily injections of testosterone given to male monkeys did not result in any specific EEG changes per se. Genital stimulation following this, however, resulted in high voltage low frequency waves mostly in the rostral hypothalamic regions. Daily injections of estrogen in female monkeys after a few days produced spontaneous spindling in the rostral hypothalamic regions, later on spreading to other areas. Genital stimulation following even the first estrogen injection produced spindling in the preoptic area. With spontaneous spindles appearing resultant to estrogen injections, genital stimulation further pronounced these.