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.

Immunohistochemical evidence for the selective involvement of dorsal root fibres in Friedreich's ataxia.

Abstract: An immunohistochemical study was carried out in order to elucidate the selective involvement of the dorsal root fibres from two patients with Friedreich's ataxia in comparison with those of 10 neurologically normal control individuals. For this purpose, antibodies to substance P and to synaptophysin were used. Substance P-immunoreactive unmyelinated fibres forming a dense network in the normal substantia gelatinosa of the spinal dorsal horn predominantly originate from a subpopulation of small cells of the dorsal root ganglia, while synaptophysin is present in virtually all nerve cell axon terminals and is useful for visualizing axon terminals in the nervous system. Strong substance P-like immunoreactivity was seen in the substantia gelatinosa of patients with Friedreich's ataxia. By contrast, there was marked depletion of synaptophysin immunoreactivity in the posterior column nuclei, with the gracile nucleus showing greater loss of positive puncta than the cuneate nucleus.

Projection of cervical dorsal root fibers to the medulla oblongata in the brush-tailed possum, Trichosurus vulpecula.

Abstract: This study describes the projection of cervical spinal afferent nerve fibers to the medulla in the brush-tailed possum, a marsupial mammal. After single dorsal roots (between C2 and T1) were cut in a series of animals, the Fink-Heimer method was used to demonstrate the projection fields of fibers entering the CNS via specific dorsal roots. In the high cervical spinal cord, afferent fibers from each dorsal root form a discrete layer in the dorsal funiculus. The flattened laminae from upper cervical levels are lateral and those from lower cervical levels are medial within the dorsal columns. All afferent fibers at this level are separated from gray matter by the corticospinal fibers in the dorsal funiculus. All cervical roots project throughout most of the length of the well-developed main cuneate nucleus in a loosely segmentotopic fashion. Fibers from rostral roots enter more lateral parts of the nucleus, and fibers from lower levels pass to more medial areas; but terminal projection fields are typically large and overlap extensively. At more rostral medullary levels, fibers from all cervical dorsal roots also reach the external cuneate nucleus. The spatial arrangement here is more complex and more extensively overlapped than in the cuneate nucleus. Rostral cervical root fibers reach ventral and ventrolateral areas of the external cuneate nucleus and continue to its rostral pole; more caudal root fibers project to more dorsal and medial regions within the nucleus. These results demonstrate that projection patterns of spinal afferents in this marsupial are similar to those seen in the few placental species for which detailed data concerning this system are available.

The Projection of Cervical Primary Fibers to the DCN of the Squirrel, Sciurus niger: Fiber Sorting in the Dorsal Columns

Abstract: The course and terminal distribution of cervical primary afferents in the dorsal column nuclei were studied in the fox squirrel, Sciurus niger. Unilateral rhizotomies were performed at cervical levels C3, C4, C5, C6 and C8. For all spinal levels studied except C8, degeneration in the medullary cuneate fasciculus was present within two distinct groups. They included a large oblique lateral lamina and a small superficial group of degeneration. The superficial group was horizontal, located medial to the large lamina and appeared to be formed by the medial shifting of fibers away from the initial larger group. Fibers in the large primary lamina appeared to terminate primarily in the ventrolateral areas of the cuneate nucleus. Fibers from the superficial group, however, appeared to project mostly to dorsal cuneate nuclear areas. Hence, the dual transverse terminal patterns for cervical fibers in the cuneate nucleus appeared to be related directly to a fiber sorting process that involved the formation of two often separate ascending fiber groups in the cuneate fasciculus. The results of this study are compared with the mechanosensory mapping of the dorsal column nuclei in the squirrel.

Nucleobindin 2/nesfatin-1 expression and colocalisation with neuropeptide Y and cocaine- and amphetamine-regulated transcript in the human brainstem.

Abstract: Feeding is a complex behaviour entailing elaborate interactions between forebrain, hypothalamic and brainstem neuronal circuits via multiple orexigenic and anorexigenic neuropeptides. Nucleobindin-2 (NUCB2)/nesfatin-1 is a negative regulator of food intake and body weight with a widespread distribution in rodent brainstem nuclei. However, its localisation pattern in the human brainstem is unknown. The present study aimed to explore NUCB2/nesfatin-1 immunoexpression in human brainstem nuclei and its possible correlation with body weight. Sections of human brainstem from 20 autopsy cases (13 males, seven females; eight normal weight, six overweight, six obese) were examined using immunohistochemistry and double immunofluorescence labelling. Strong immunoreactivity for NUCB2/nesfatin-1 was displayed in various brainstem areas, including the locus coeruleus, medial and lateral parabrachial nuclei, pontine nuclei, raphe nuclei, nucleus of the solitary tract, dorsal motor nucleus of vagus (10N), area postrema, hypoglossal nucleus, reticular formation, inferior olive, cuneate nucleus, and spinal trigeminal nucleus. NUCB2/nesfatin-1 was shown to extensively colocalise with neuropeptide Y and cocaine- and amphetamine-regulated transcript in the locus coeruleus, dorsal raphe nucleus and solitary tract. Interestingly, in the examined cases, NUCB2/nesfatin-1 protein expression was lower in obese than normal weight subjects in the solitary tract (P = 0.020). The findings of the present study provide neuroanatomical support for a role for NUCB2/nesfatin-1 in feeding behaviour and energy balance. The widespread distribution of NUCB2/nesfatin-1 in the human brainstem nuclei may be indicative of its pleiotropic effects on autonomic, neuroendocrine and behavioural processes. In the solitary tract, a key integrator of energy status, altered neurochemistry may contribute to obesity. Further research is necessary to decipher human brainstem energy homeostasis circuitry, which, despite its importance, remains inadequately characterised.

Neurogenesis of cuneothalamic neurons and NO-containing neurons in the cuneate nucleus of the rat

Abstract: The genesis of the cuneothalamic neurons (CTNs) in the rat cuneate nucleus was determined by a double-labeling method using 5′-bromodeoxyuridine (BrdU), the thymidine analogue, and Fluoro-Gold (FG), a retrograde fluorescent tracer. BrdU-positive cells were observed in the cuneate nucleus in all rats receiving BrdU injection at embryonic days (E) E13–E16; none was detected in rats given BrdU injection at E12. At E13 and E14, BrdU-positive cells were randomly distributed. However, at E15, the number of BrdU-positive cells was clearly reduced and the majority of them was located at the dorsolateral or peripheral region of the nucleus. FG/BrdU double-labeling study showed the existence of BrdU-labeled CTNs when the mother rat received BrdU injection at E13 and E14, being more numerous at E13 in which the neurons were scattered throughout the nucleus. At E14, however, the majority of the BrdU-labeled CTNs were located superficially in the nucleus. Double-labeled cells were undetected in rats that had been exposed to BrdU at E15 and E16. Quantitative data showed that the majority (ca 70–80%) of the CTNs were generated at E13, and were markedly decreased at E14 (ca 4–6%). Using nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) histochemistry coupled with BrdU immunohistochemistry, we have shown the NADPH-d/BrdU double-labeled neurons in the nucleus between E13 and E15, with the majority of them occurring at E14, but absent at E16. The present results suggest that the CTNs are generated prior to the NO-containing neurons in the cuneate nucleus.