Hippocampal and cortical activity during sexual behavior in the female rat.

Hippocampal and cortical activity were studied during sexual behavior in the female rat. Hippocampal theta appeared during her soliciting behavior. High-frequency theta accompanying the male's pursuit slowed when the male mounted the female and then increased in frequency during the brief continuation of lordosis following mounts without vaginal penetration. During prolonged lordosis after intromissions and ejaculations, slow theta continued. No changes in cortical frequencies were observed during mounts, intromissions, or ejaculations. During immobility (standing, sitting, and lying down) hippocampal activity became slow and irregular. High-amplitude hippocampal and, eventually, cortical spindles developed during immobility as sexual exhaustion was approached. Immobility and its accompanying electroencephalographic spindling are interpreted as indicative of a sexual satiety or inhibitory process.