Clinically relevant basic science studies of gender differences and sex hormone effects.

Ovarian steroids produce a variety of effects on the brain, influencing diverse nonreproductive processes such as cognitive function, motor activity, seizure susceptibility, and pain sensitivity, as well as pathological processes such as Parkinson's disease and Alzheimer's disease. Studies of ovarian hormone effects on animal brains have revealed a wide array of neurochemical and structural effects of ovarian steroids, which are reviewed in this article. These studies provide a foundation for understanding hormone effects on mood, behavior, and cognition in the menstrual cycle, during reproductive transitions and in depressive illness.