The persistence of a normally transient cerebrocerebellar pathway in the cat

A direct, although transient, projection from the sensorimotor cortex to the cerebellum has been described previously in the neonatal kitten. The present report demonstrates that this pathway can be induced to persist into juvenile stages of the cat by partially denervating the deep cerebellar nuclei. Most of the cerebellar cortex on one side was removed in kittens within the first week after birth, but the deep cerebellar nuclei were preserved, in an effort to destroy most of the input into the deep nuclei. After 6-11 weeks the remaining white matter and deep nuclei on the lesioned side were injected with WGA-HRP in most of the animals, while a few received injections of either WGA-HRP or HRP in the sensorimotor cortex ipsilateral to the lesion. Results from these experiments showed that the normally transient cerebrocerebellar pathway persisted to some degree in young adults lesioned as neonates. However, the functional significance of this pathway, as well as other transient pathways, is still unknown.