Effects of vestibulospinal lesions upon locomotor function in cats.

We used cats to study the consequences of bilateral ablation of the vestibular complex. The animals were very severely ataxic and incapable of head support for nearly two weeks. They gradually regained the ability to stand and to walk on a treadmill, at first with a marked reduction of the extensor components of stepping. After stabilization of recovery we could not obtain decompensation by dorsal hemisection. We conclude that the key consequence of these lesions is a temporary reduction in facilitatory drive to joint extensor muscle groups. Neither the corticospinal nor the rubrospinal tracts mediate the functional recovery observed.