FEATURES OF PLASTIC VARIABILITY IN BILATERALLY ORGANIZED LINKS OF CEREBELLO- AND VESTIBULOTHA-LAMIC SYSTEMS
In adult cats the features of distribution and morphological structure of neuronal populations of the cerebellar fastigial nucleus and the lateral vestibular nucleus of Deiters bilaterally projecting to the partly deafferented ventrolateral nucleus of the thalamus was studied. Partial deafferen-tation of ventrolateral nucleus was evoked by preliminary (for three months) electrolytic destruction of the contralateral nucleus interpositus of the cerebellum or the lateral vestibular nucleus of Deiters. The method of retrograde axonal transport of horseradish peroxidase with local administrations of marker in the ventrolateral nucleus of the thalamus was used. Labeled neurons of Dei-ter's nucleus, the sources of contralateral projections to the ventrolateral nucleus of the thalamus are presented by population of giant cells; as sources of the ipsilateral projections are large cells, but significantly smaller than giant cells. In the fastigial nuclei of the cerebellum labeled cells were observed bilaterally and were represented by two populations of neurons: one with diffuse distribution, the other has a distinct symmetrical localization in both the paired nuclei. It is assumed that a possible mechanism underlying the reorganization of the projections as a symmetrical neuronal population of fastigial nucleus and various by the morphological structure of Deiter's nucleus might ingrowths as fibers in the deafferented area.