Brain stem and cerebellar lesions in female rats. II. Lordosis reflex.

The effects of brain stem and cerebellar lesions upon the lordosis reflex were studied. Lesions of the lateral vestibular nucleus (LVN) and nucleus reticularis gigantocellularis (NGc) produced significant deficits in lordosis. Lesions of the deep cerebellar nuclei, inferior olive, medial vestibular nucleus, and superior vestibular nucleus did not produce significant effects. Results from animals with lesions of both lateral vestibular nucleus (LVN) and nucleus gigantocellularis (NGc) suggested that these structures act independently in their control of lordosis. Histological analysis showed that giant cell loss in NGc and Deiters' cell loss in LVN were both significantly correlated with decrements in lordosis. These results indicate that lateral vestibulospinal and reticulospinal pathways participate in the descending control of segmental mechanisms responsible for the lordosis reflex.