Localization of thalamic projection of afferents from the tongue in the cat

Author:
Publisher website
Google Scholar
Abstract
Neuroanatomical nuclear configuration corresponding to the projection regions for the chorda tympani, the IXth, and the lingual nerves was studied in the cat thalamus by a combination of electrophysiological, stereotaxic, and histological techniques. Each of the three nerves innervating the tongue was dissected for stimulation in cats deeply anesthetized with Nembutal. Maps of the extent of the thalamic projection for a particular nerve were obtained by recording evoked potentials in the thalamus during the stimulation of one of these nerves. Such maps were correlated with the anatomical structures of the cat thalamus by reconstructing the recording sites from histological sections of the cat brain. It was found that the chorda tympani and the IXth nerve projection regions correspond closely to the ventromedial nuclear complex with slight encorachment on the lingual nerve projection region in the ventrobasal complex. The most medial portions of the taste nerve projection regions do not relay any tactile afferent impulses and the most lateral portion of the lingual nerve projection is not activated by impulses in the taste nerves. Therefore, it is suggested that the thalamic relay of taste is not coextensive with other lingual modalities in the cat thalamus but it has an independent representation in the ventromedial nuclear complex.