Interactions between spinocervicolemniscal and dorsal column pathways in thalamic ventrobasal neurons in the cat.

Ventrobasal (VB) thalamic cells responding to electrical stimulation of the dorsal column (DC) and of the dorsolateral funiculus DLF in cats with DC intact or cut at C4 and isolated, were studied. Among the cells observed, about 30% showed convergence to the two pathways. Different patterns of interaction between the two inputs were found, but the most frequent effect observed was an inhibition exerted by dorsal column (conditioning) stimulation on the activity evoked by dorsolateral funiculi (test) stimulation. From these results a dominance of the DC over the spinocervico-thalamic (SCT) inputs was confirmed.