[Lemniscal afferent projections to the caudate nucleus in the cat]

Abstract

Lemniscal and extralemniscal somatosensory afferent projections from the foreleg to the caudate nuclei were studied in cats under ethaminalsodium anaesthesia. To differentiate the projections, two groups of animals were used, in one of which simultaneous bilateral elimination of the lemniscal system was carried out, and a unilateral elimination in the other one. It was shown by the evoked potentials (EP) method that both caudate nuclei along with the structures of the ventro-basal complex receive somatosensory afferentation from the forelegs with the same latency. Kinesthetic impulse activity transmitted by the lemniscal system comes from the stimulated foreleg to the ipsilateral structures of the forebrain along twice crossed pathways (at the medullar and, probably, the diencephalon level), since EPs in the caudate nucleus on the side of the section of the midbrain tegmentum persist in response to stimulation of the ipsilateral limb and disappear after section of the medial lemniscus.