Lordosis behaviour in male rats: effect of deafferentation in the preoptic area and hypothalamus

Differentiation of sexual behavior patterns in male rats is dependent on the internal secretion of testes dur ing neonatal life. Removal of the testes at this time causes feminization and results in male rats which display female patterns of sexual behavior (Gorski, 1971). Female patterns of behavior are usually rare in normal male rats but recently the authors found that transection of the dorsal afferent neurones to the preoptic and anterior hypothalamic areas potentiated the display of lordosis in hormonally primed male rats (Yamanouchi & Arai, 1975). In the present study, further neuroanatomical analysis was carried out to clarify the localization of the afferent pathway involved in the regulation of lordosis behavior.