The spino - cerebellar tracts in rabbit.

In young mature rabbits the spinal cord was damaged within lateral funicles and adjacent parts of the dorsal and ventral funicles. After 5-8 days of survival, control examinations were performed to find the extension of the lesion of the spinal cord, as well as studies of the cerebellum by Nauta method to investigate the site of the changed nervous fibres. After injuring the spinal cord on the level of neuromer C3 the degeneration of nervous fibres was found on both side within the anterior and posterior lobes of the cerebellum. In the anterior lobe the degeneration referred to lobules I up to the anterior part of lobule V; in the posterior lobe it referred to lobule VIIIa, and VIIIb of the vermal zone, as well as to the adjacent parts of the hemispheres. When the spinal cord was damaged on the level of neuromer Th7 the degeneration of nervous fibres was seen in the same regions of the cerebellum, but mainly on the side of the lesion. When the spinal cord was damaged on the level of neuromer L2 the fibres changed by degeneration were met within the same regions of the anterior and posterior lobes of the cerebellum, but mostly on the side opposite the lesion. The changes were smaller in this region than in the two kinds of lesions discussed before. The results allow to assume that the ventral and dorsal spinocerebellar tracts end in the same regions of the cortex of the vermal zone and the intermediate zone of the anterior and posterior cerebellar lobe. The dorsal spinocerebellar tract seems to end on the same side, while the ventral spino-cerebellar tract ends almost exclusively on the opposite side of the symmetry plane.