An electron microscopic study of the corticorubral fibers after neonatal deep cerebellar nuclear lesions in albino rats.

After a lesion in the sensorimotor and adjacent cortex in normal adult rats, degenerating terminals showing the dense reaction form asymmetrical contacts with spines, dendrites of various sizes, soma and other axonal terminals. Filamentous degeneration is also present. After neonatal deep cerebellar nuclear lesions involving the dentate nucleus and the adjacent interposed nucleus, the cerebrocorticorubral fibers form similar synaptic contacts with somatic, dendritic and axonal profiles. The incidence of axo-dendritic contacts on spine is reduced, while that of axo-dendritic contacts on small, medium-sized and large dendrites and axo-somatic contacts is increased.