The medial preoptic area is involved in both sexual arousal and performance in male rats: re-evaluation of neuron activity in freely moving animals.

A total of 74 single unit activities was recorded from the medial preoptic-anterior hypothalamic continuum (MPOA) during free copulatory behavior of male rats. Forty-six units (62.2%) showed changed activities during at least one phase of male copulatory movements; 26 units (35.1%) increased in the firing rate during pelvic thrusting; 32 units (43.2%) increased in activity during backward jumping immediately after intromission; only one unit (1.4%) showed decreased firing rate during thrusting and backward jumping; 12 units (16.2%) increased in activity during pursuit of a female; 19 units (25.7%) were suppressed during genital grooming. Furthermore, 67 units (90.5%) showed a significant change in activity throughout a series of copulatory behavior. From the introduction of a female up to ejaculation, relatively large number of units increased in the firing rate above the value during pre-introduction adaptation period. During postejaculatory interval, however, most units decreased in activity below the level during copulation. These results strongly suggest that the MPOA is involved in both sexual arousal and performance in male rats.