Cuneate nucleus

About: Cuneate nucleus is a research topic. Over the lifetime, 614 publications have been published within this topic receiving 24859 citations. The topic is also known as: cuneate nucleus of spinal cord.

Projections of the cerebellar and dorsal column nuclei upon the inferior olive in the rhesus monkey: an autoradiographic study.

Abstract: Projections from the cerebellar and dorsal column nuclei to the inferior olive of the rhesus monkey were traced with anterograde autoradiographic methods. The cerebellar nuclei give rise to a massive projection which reaches the contralateral inferior olivary complex by way of the descending limb of the superior cerebellar peduncle. Dentato-olivary fibers project exclusively upon the principal olivary nucleus (PO) and observe a strict topography. The dorsal, lateral, and ventral dentate project respectively to the dorsal, lateral, and ventral lamellae of the PO. Within the lamellae, the dentato-olivary fibers are related point for point in the medio-lateral axis. By contrast, the rostro-caudal topography is reversed so that the rostral pole of the dentate projects to the caudal PO and the caudal dentate to the rostral PO. These connections are predominantly crossed but a small ipsilateral component recrosses the midline at the olivary commissure and mirrors the topography on the opposite side. The anterior interpositus projects only to the medial half of the DAO and the posterior interpositus projects only to the rostral two thirds of the MAO. The ipsilateral component is minor in comparison with the contralateral projection, but appears to be more substantial than the ipsilateral projection to the PO arising from the dentate nucleus. The fastigial nucleus does not project upon the olivary complex. The dorsal column nuclei project topographically upon the contralateral accessory nuclei with the gracile nucleus sending fibers primarily to the lateal half of the DAO and the cuneate nucleus projecting to rostral cell groups of the MAO. The present results when compared with other olivary connections described by previous studies in a veriety of species suggest that regions of the MAO and DAO receiving sensory information from the periphery may lie outside the influence of cerebellar feedback loops.

Central projections of C4-C8 dorsal root ganglia in the rat studied by anterograde transport of WGA-HRP.

Abstract: Injections of WGA-HRP were made in the rat C4-C8 dorsal root ganglia (DRGs) individually to study the central projections and their relations to each other. The main dorsal horn projections from these DRGs to the dorsal horn lamina II extended for about two segments rostrally and caudally to the injected DRG, whereas the projections to laminae I, III, and IV were less restricted rostrocaudally. Comparisons of the dorsal horn projections from the DRGs investigated indicated a tendency for a somatotopic organization, which was most prominent in lamina II. Labeled central branches from the C4-8 DRGs could be traced in the dorsal column as far caudally as 12-17 segments caudal to the level of entrance. Most of these fibers appeared to end in the medial dorsal horn base, including the column of Clarke. Labeling of primary afferents in the ventral horn generally extended for at least 3-4 segments rostral and caudal to the level of the injected DRG. Projections to the central cervical nucleus were most prominent from the C4 DRG and gradually became less prominent from the more caudal DRGs. Heavy projections to the cuneate nucleus (Cun) originated from the C7 and C8 DRG, whereas those from the C4-C6 DRGs were less extensive. The Cun projections from the different DRGs appeared to overlap, and the same was true for the projections to the external cuneate nucleus. Projections to the gracile nucleus, the vestibular nuclear complex, including nucleus X, and to trigeminal sensory nuclei were seen from all DRGs investigated.