The effect of medial preoptic--anterior hypothalamic lesions on bisexual behavior of the male rat.

The effects of bilateral radiofrequency lesions in various parts of the medial preoptic area (mPOA) and anterior hypothalamus (AH) on masculine and hormone induced feminine sexual behavior was studied in male rats. Anatomical as well as statistical analysis of the extent and location of the lesions and the consequent behavioral changes indicated that different parts of the mPOA-AH continuum are involved in masculine and feminine sexual behavior in different ways. Bilateral destruction at the transition of the mPOA and AH resulted in a large reduction of masculine sexual activity while lesions concentrated in the AH slightly facilitated feminine sexual behavior in males. These results are consistent with the notion that the mPOA-AH continuum is divided into anatomically and functionally different parts.