Response patterns of vestibulospinal neurons to lumbar rotation in decerebrate rats.

In vestibulospinal neurons projecting to the lumbar enlargement, activities were modulated in response to alternate tilts of the caudal body around the vertebral axis. Three types of neurons were found: Type I (37.8%) showed faster firing during the ipsilateral side-down tilt; type II (51.1%) showed the reverse pattern; type III were unaffected. Types I and II may be important in the tonic lumbar reflex.