[Neuronal populations: sources of the corticothalamic projections to the partially deafferented ventrolateral...

The features of distribution and morphological structure of the motor cortex neuronal populations projecting to the cerebellar-recipient ventrolateral nucleus of the thalamus after its partial deafferentation were studied in adult cats. The partial deafferentation of the ventrolateral nucleus was evoked by preliminary (three months) electrolytic destruction of the contralateral interpositus nucleus of the cerebellum. The method of retrograde axonal transport with local introductions of the marker was used. All labeled neurons were presented by populations of non-pyramidal neurons and small and medium-sized pyramids, which were distributed in the deep cortical layers: in a lower layer division of V and mostly in layer VI. The labeled neurons were observed in cortical fields 4γ and field 6αβ. The data obtained showed no structural reorganization of cortical projections to the deafferented ventrolateral nucleus of the thalamus. It is assumed that this is due to the high degree of specialization of the studied system, triggering the motor program. Neuroplastic changes manifested in the abnormal transformation of proximal portions of dendrites and presence of a large number of "paired" pyramidal neurons compared to intact animals.