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Somatotopic organization in the spinal trigeminal nucleus, the dorsal column nuclei and related structures in the rat

1967; Wiley; Volume: 130; Issue: 4 Linguagem: Inglês

10.1002/cne.901300406

1096-9861

Samuel G. Nord,

Vestibular and auditory disorders

Abstract The medulla of the anesthetized rat was explored with with fine (25.4 μ) wire electrodes from C 1 rostrally to the cerebellar penduncles. Concurrently, the body surface and the buccal cavity were mechanically stimulated with delicate probes. Descriptions of peripheral fields and characteristics of evoked discharges were recorded. Histological evidence revealed that the dorsal column nuclei yeilded responses to stimulation of the limbs, trunk, posterior face and pinna. The spinal trigeminal nucleus indicated an input from the face and from buccal cavity components, while the solitary nucleus disclosed an input originating in the tongue and, less often, in other oral structures. In addition, loci in adjacent portions of the reticular formation gave responses to mild stimulation of many peripheral regions. Most of the body projected to every level of the medulla studied. The projection was typically homolateral, and fields of many sizes were represented throughout the longitudinal extent of each nucleus. The amount of bulbar tissue devoted to any region of the body appeared to be related to the innervation density of that region. The results support the concept that the nuclei can be regarded together as a functional unit which resembles the primary tactile systems of the thalamus and the cortex in somatotopic organization.