Differential Effects of Lesions in Three Limbic Areas on Ultrasound Production and Lordosis by Female Hamsters

Ultrasound production and lordosis were examined in ovariectomized, hormone-primed female hamsters before and after sham operations or bilateral electrolytic lesions in the lateral septum/bed nucleus, corticomedial amygdala, or lateral habenula. During 2-min exposures to synthetic ultrasounds and 1-min exposures to stimulus males, females with corticomedial amygdala lesions exhibited reduced ultrasound rates and lordosis durations. Following lesions in the lateral septum/bed nucleus, females showed significant increases in ultrasound rates with no pre- to postoperative change in lordosis. Ablations of the lateral habenula had no effect on calling but were associated with shorter lordosis durations. These results demonstrate that two reproductive behaviors, ultrasound production and lordosis, are differentially affected, depending on lesion placement within the limbic system. In turn, these differences demonstrate that the neural mechanisms for two elements of a single major class of behavior can be quite distinct, both in terms of the likelihood that particular brain areas will be involved and in the nature of their involvement.