[Convergence of projections from various thalamic nuclei on the rat somatosensory cortex columns]

The method of primuline fluorochrome retrograde transport was used to study sources of thalamo-cortical projections on a separate somatic cortical neuronal column connected with C3 vibrissae of albino rat. Labeled cells were found in 8 thalamic nuclei: tv, tvd, tpo, pf, rh, tvm, tvl, tr. The intensity of neuron staining and cell quantity and density varied in different nuclei. Hence their axon branching in the rat cortex was also different. The majority of intensively stained and densely packed cells have been observed in tv nucleus. The observed convergence of different thalamo-cortical inputs on single somatic cortex column explains heterogeneity in functional properties of the same column neurons and makes it possible for the column to form several neuronal assemblies with different functions.