Plasticity in vestibular and spinal circuits after hemilabyrinthectomy in the frog.

Removal of the labyrinthine organs on one side results in static and dynamic disturbances. Some functional recovery is seen in frogs over time. Electrophysiological studies of the isolated brainstem and/or spinal cord of hemilabyrinthectomized frogs demonstrate changes in vestibular and spinal circuits. Comparison of the time courses of these changes with the known time course of postural recovery excludes changes in the vestibular nuclei as an explanation for the initial postural recovery process. Selective labyrinthine lesion suggest a causal link between utricular lesion, postural deficit, spinal plasticity and postural normalization.