Collateral sprouting of cerebral cortical fibers in the red nucleus following destruction of the interpositus nucleus may be effective in restoring activity of rubral neurons. Shrinkage of the deafferented red nucleus was measured to estimate its effect on recording neural activity and its contribution as a stimulus for sprouting. The results suggest that rubral morphology is preserved during the early time course of collateral sprouting when electrophysiological changes are evident.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25091/1/0000522.pd