Showing papers on "Cuneate nucleus published in 1993"
TL;DR: Transganglionic labelling (WGA-HRP) demonstrated that some of the CO-blotches in the rat CN are related to the terminal projection fields of primary afferents from the skin of the forepaws, which supports a tripartite rostrocaudal division in theRat CN, similar to that described by other investigators in cats, monkeys and raccoons.
40 citations
TL;DR: Results indicate that fetal forelimb amputation results in anatomical expansion of the central projections of hindlimb afferents into the cuneate nucleus, which appears weakly expressed in the receptive fields of cunesate neurons.
Abstract: A previous study has shown that fetal forelimb removal in the rat results in an increase in the size of the hindlimb representation in primary somatosensory cortex and suggested that this anomalous cortical organization may have resulted from alterations in the primary afferent innervation of the dorsal column nuclei (Killackey and Dawson, 1989). The present study used both anatomical and electrophysiological techniques to examine the effects of fetal forelimb amputation on the dorsal column nuclei. Rats sustained forelimb removals on embryonic day 16 and were used in terminal experiments when they reached adulthood (> 60 d of age). Analysis of cytochrome oxidase-stained sections demonstrated that the cuneate nucleus ipsilateral to the lesion decreased in volume by an average of 36.7% (N = 7, p < 0.001, paired t test), but there was no corresponding increase in the volume of the gracile fasciculus and nucleus. Bilateral application of HRP to the sciatic nerves demonstrated that axons that innervate only the gracile nucleus on the intact side of the brainstem were present in the cuneate nucleus on the deafferented side. Injection of HRP into the skin overlying the point of the amputation (the stump) indicated that axons innervating this region filled most of the dorsal one-half of the shrunken cuneate nucleus and overlapped with the sciatic nerve afferents innervating the cuneate on this side. Mapping the receptive fields of multiple unit clusters demonstrated that most recording sites in the shrunken cuneate nucleus were activated by inputs from the stump and adjacent skin. In addition, 9.1% (N = 30) of such unit clusters (N = 328) could also be excited by stimulation of the hindlimb. These were observed in only three of the nine experiments. Unit clusters with split receptive fields including the skin overlying the stump and the hindlimb were located throughout the rostrocaudal extent of the cuneate nucleus. These results indicate that fetal forelimb amputation results in anatomical expansion of the central projections of hindlimb afferents into the cuneate nucleus. This anatomical organization appears weakly expressed in the receptive fields of cuneate neurons.
35 citations
TL;DR: It is speculated from this study that the incoming impulses from the forelimb area are modulated by the GABA-immunoreactive boutons in the cuneate nucleus of the rat.
20 citations
TL;DR: The serotoninergic innervation of the dorsal column nuclei (DCN) was investigated in cats and owl monkeys with immunohistochemical methods and showed that the labeled fibers were thin and unmyelinated.
Abstract: The serotoninergic innervation of the dorsal column nuclei (DCN) was investigated in cats and owl monkeys (Aotus trivirgatus) with immunohistochemical methods. A dense network of serotonin-immunoreactive fibers was present in the reticular regions of DCN in cats, and in the pars triangularis of the cuneate nucleus and the peripheral and caudal regions of the gracile nucleus in owl monkeys. The cat's cluster regions and the monkey's rotund regions were more sparsely innervated. Electron microscopic examination showed that the labeled fibers were thin and unmyelinated. Vesicle-containing, terminal-like structures were small. They were in contact with dendrites, other terminals and cell bodies, but synapses were rare.
The results demonstrate that the serotoninergic projection to the DCN in both cats and owl monkeys is heterogeneously distributed in a pattern that is faithfully related to the cytoarchitectonic subdivisions of the DCN. The densely innervated reticular regions in the DCN of cats and the corresponding regions in monkeys are predominantly involved in the processing of sensory information to the cerebellum, either directly, or indirectly through projections to the inferior olive, pontine gray, tectum, pretectum, red nucleus, or zona incerta. Thus, the present findings suggest that the serotoninergic innervation of the DCN is primarily related to the DCN's involvement in motor functions. © 1993 Wiley-Liss, Inc.
18 citations
TL;DR: Dense patches of p75NGFR-like immunoreactivity appear to correspond to the 'blotches' of cytochrome-oxidase activity observed in the middle region of the CN, which suggests an important role for trophic factors in the CN's development and/or maintenance.
13 citations
TL;DR: In rats that sustained forelimb removals at birth or transection of the brachial plexus in adulthood, dense galanin immunoreactivity was present throughout the cuneate nucleus at all rostrocaudal levels on the side of the brainstem ipsilateral to the lesion.
Abstract: Rats that sustained forelimb removal on either embryonic day (E) 16, on the day of birth (P-0), or transection of the brachial plexus in adulthood had brainstem sections stained for galanin, calcitonin gene-related peptide (CGRP), or substance P (SP) at various intervals after these lesions were made. In normal adult rats, only a few galanin-immunoreactive fibers are present in the cuneate nucleus and most are located in its caudal portion. CGRP-positive axons are also sparse in the cuneate and are distributed mainly in the periphery of the nucleus. SP-positive axons are seen throughout the cuneate nucleus. In rats that sustained forelimb removals at birth or transection of the brachial plexus in adulthood, dense galanin immunoreactivity was present throughout the cuneate nucleus at all rostrocaudal levels on the side of the brainstem ipsilateral to the lesion. The changes after lesions that were made in the adult animals were apparent within 1 week, the earliest time analyzed. Increases in galanin immunoreactivity in the cuneate of animals that sustained forelimb removals on P-0 were first visible on P-2. Neither forelimb removal at birth nor brachial plexus lesions in adulthood had any qualitative effect upon the distribution or density of CGRP- or SP-immunoreactivity in the cuneate nucleus. Removal of a forelimb on E-16 did not increase the density of galanin-immunoreactive fibers in the cuneate nucleus. Such lesions also failed to produce any appreciable change in the density of either CGRP- or SP-positive fibers in the cuneate nucleus. The present data raise the possibility that large caliber, non-peptidergic primary afferent axons which innervate the cuneate nucleus may express galanin after damage at birth or in adulthood.
12 citations
TL;DR: Effects on spinal motoneurons and on thalamocortical projection cells in the lateral geniculate nucleus following deafferentation are confirmed and attempts to define a time course for the reduction in transport by lemniscal projection cells revealed an effect that was dramatic in some animals, partial in others, and not demonstrable in the remainder, without a clear relationship to time after surgery.
11 citations
Journal Article•
TL;DR: Although INAD is a generalized neurodegenerative disease, it is suggested that the primary disorder might occur in the neurons and axons of the sensory tracts.
Abstract: We performed pathological studies on the central and peripheral nervous systems of cases with infantile neuroaxonal dystrophy (INAD). Numerous spheroid bodies in the central and peripheral nervous systems, were seen and divided into large spheroid bodies (LSB) and small spheroid bodies (SSB) photo-microscopically. LSB had a relation to some specific neurons with weak expression of neuron specific enolase, neurofilament and chromogranin using PAP method. SSB showed a relation to the axon without immunohistochemical expression of neuron specific enolase, neurofilament, glial fibrillary acidic protein, myelin basic protein, chromogranin, S 100 protein or antitrypsin. LSB were prominent in the posterior column, gracile nucleus, cuneate nucleus, and the tegmentum of the midbrain and the pons associated with neuronal loss and gliosis. SSB were observed in the thalamus, basal ganglia and the cerebral cortex. The cerebellum was sclerotic with few microtubule-like structures disposed in a dense network in association with degenerated mitochondria. Similar changes were observed in the sural nerves, autonomic nerve endings in the skin, and the nerve plexus of the digestive tract. Although INAD is a generalized neurodegenerative disease, it is suggested that the primary disorder might occur in the neurons and axons of the sensory tracts.
10 citations
TL;DR: It is proposed that individual neurons receiving viscerosomatic convergence may have the capacity for being involved in several different functions, where the function at any given time depends on the overall behavioral and physiological circumstances of the organism and the overall pattern of activity of other neurons in the nervous system.
Abstract: M uch of the initial portion of the focus article introduces the reader to information on viscerosomatic convergence. This includes sections on the pervasiveness of viscerosomatic convergence and coordinating responses of visceral and somatic systems to meet the needs of a behaving organism. Dr. Berkley importantly stresses that there is substantial integration of these systems with relatively little understanding about how that integration takes place. In the most general sense, I certainly agree with these discussions. In the latter portion of the focus article, Dr. Berkley provides more specific views about how integration might take place. Dr. Berkley proposes that individual neurons receiving viscerosomatic convergence may have the capacity for being involved in several different functions, where the function at any given time depends on the overall behavioral and physiological circumstances of the organism and the overall pattern of activity of other neurons in the nervous system. For example, a possible scenario suggested by Dr. Berkley is that "when neurons in a certain part of the cuneate nucleus are active at the same time as certain neurons in specific parts of the solitary nucleus, nucleus ambiguus, zona incerta, orbital cortex, and intermediolateral spinal grey, then pain imprecisely localized within the thoracic cavity and on the forearm is experienced and the heartbeat interval changes. By contrast, when those cuneate neurons are active at the same time as neurons in the ventrobasal complex and red nucleus, but not in the solitary nucleus, nucleus ambiguus, etc., then some sort of tactile experience occurs that is more precisely local-
1 citations