Impaired lordosis response in golden hamsters with lesions in the ventromedial midbrain.

Lesions in the ventromedial midbrain tegmentum of female golden hamsters produced various degrees of impairment of the lordosis response to male hamsters or manually delivered somatic stimuli. The most severe deficits were produced by anterior lesions, whereas larger, more posterior lesions sometimes produced no lordosis impairment. In tests where lordosis was not completely eliminated, the lesions tended to impair maintenance rather than elicitation of lordosis, thus constituting a different behavioral effect from that associated with deep tectal or central gray lesions in this species.