bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dynamic changes in the density of radial glial fibers of the developing murine cerebral wall: A quantitative immunohistological analysis
Authors: Gadisseux J. F. , Evrard Ph. , Misson J. P. , Caviness V. S. 
Published: January 2005

AbstractThe density of radial glial fibers in the developing murine cerebral wall decreases dramatically during the terminal week of gestation. The present analysis characterizes these variations of fiber density quantitatively. Radial glial fibers were stained with monoclonal antibody RC2. Fibers were counted in a standard area of 2,000 μm2, passing orthogonally to the fiber long axis.At E14, fiber density is maximum and relatively uniform throughout the full width of the cerebral wall. Subsequently, the overall glial fiber density decreases and fiber density gradients emerge in the transmural span of fibers. These, radial fiber density gradients are marked by sharp declines at the level of the ventricular‐subventricular zone and in the zone of transition between intermediate zone (IZ) and cortical plate. In the interval E14‐P0, the decrease in densities of fibers crossing the IZ is commensurate with the predicted diluting effects of tissue expansion with growth. By contrast, the decrease in fiber densities in ascent across the cortical plate beyond E14 through E17 exceeds that predicted by growth. The observations suggest that a substantial population of radial glial fibers do not span the full ventricular zone to the cerebral surface. A major contingent appears to extend only as far as the external sagittal stratum/ subplate through E16.Subsequently, at a time when supragranular cortical layers are being assembled, the full set of fibers appears to extend more uniformly through the cortical strata. The late surge of fibers would be appropriate to the intercalation of groupings of neurons of the supragranular layers. © 1992 Wiley‐Liss, Inc.
Time course of dorsal root axon regeneration into transplants of fetal spinal cord: I. A light microscopic study
Authors: Itoh Yasunobu , Sugawara Taku , Kowada Masayoshi , Tessler Alan 
Published: January 2005

AbstractCut dorsal root axons regenerate into intraspinal transplants of fetal spinal cord and establish synaptic connections there. The aims of the present study were to describe the progression of dorsal root growth within the transplants and the maturation of transplant morphology and to determine whether the regenerated dorsal root axons persist within the transplants or eventually withdraw.Embryonic (E) day 14 spinal cord was grafted into the lumbar enlargement of adult Sprague‐Dawley rats, and the L4 or L5 dorsal root was cut and juxtaposed to the transplants. The morphology of the transplants was examined from 1 day to over 1 year after surgery, and the regenerated dorsal roots were labeled with immunohistochemical methods to study the subset that contains calcitonin gene‐related peptide (CGRP).Embryonic spinal cord transplants survived and grew within the host spinal cord in over 90% of the animals. Transplant volume increased and the morphology of the transplants matured over the first 12 weeks and then did not change for 48–60 weeks. During the first week the transplants were composed of dissociated neurons, glia, and hematogenous cells with considerable extracellular space between them. Subsequently, the grafted neurons became densely aggregated, and non‐neuronal elements such as inflammatory cells and myelin debris disappeared. CGRP‐immunoreactive dorsal roots began to regenerate into the transplants within 24 hours, formed dense bundles by 4 days, and were still present at 60 weeks, the longest survival period examined. Myelination of axons within transplants began at 2 weeks. Quantitative analysis showed that the area of the transplants occupied by CGRP‐labeled axons and the distribution area of the labeled axons within the transplants increased until 12 weeks and persisted unchanged for over 48 weeks.These results indicate that regenerated dorsal root axons are permanently maintained within transplants of embryonic spinal cord and suggest that the transplants can contribute to the permanent restoration of damaged intraspinal neural circuits. © 1992 Wiley‐Liss, Inc.
The auditory cortex of the mouse: Connections of the ultrasonic field
Authors: Hofstetter Kurt M. , Ehret G. 
Published: January 2005

AbstractThe cortical and subcortical connections of the ultrasonic field (UF) of the auditory cortex of the house mouse (Mus musculus) were studied by using retrograde and anterograde transport of horseradish peroxidase (HRP). Small amounts of HRP were locally injected into the electrophysiologically defined UF. Superficial (layer I–IV) and deep (layer IV–VI) injections were prepared.Superficial injections led to labelling of both cells (retrograde) and terminals (anterograde) in areas of the ipsilateral primary and secondary auditory cortex and in its dorsoposterior field, in an ipsilateral dorsal association area (patches of label), probably in ipsilateral secondary somatosensory cortex, in the contralateral homotopic UF, and in the ipsilateral medial geniculate body (MGBv, MGBd, and MGBm) and caudal posterior nucleus complex.Deep injections showed the same connectivities as superficial ones and, in addition, terminals in the very caudal caudatoputamen, in the nucleus limitans and the nucleus reticularis of the thalamus, in the rostral pole, the dorsomedial, and lateral nucleus of the inferior colliculus, in the stratum griseum intermediale of the superior colliculus, and in a pontine nucleus ventromedial of the lateral lemniscus. All these projections occurred only ipsilaterally.The majority of connections, except those with the nucleus limitans, superior colliculus and pontine nucleus, suggest that UF is part of the primary anditory cortex (AI) and/or of the anterior anditory field (AAF) of the auditory cortex. Since UF has no regular tonotopy, this has important implications for the functional role that AI/AAF can have in communication‐sound analysis. © 1992 Wiley‐Liss, Inc.
Quantitative analysis of bulbospinal projections from the rostral ventrolateral medulla: Contribution of C1‐adrenergic and nonadrenergic neurons
Authors: Jeske Iwona , McKenna Kevin E. 
Published: January 2005

AbstractThe contribution of C1‐adrenergic and nonadrenergic neurons to the spinal projection from the rostral ventrolateral medulla (RVLM) and their relative innervation density throughout thoracic spinal segments were examined by combining the Fluorogold (FG) retrograde tracing technique with immunofluorescent labeling for the epinephrine‐synthesis enzyme phenylethanolamine N‐methyltransferase (PNMT). The results indicate that the RVLM‐spinal projection is comprised of both PNMT‐positive and PNMT‐negative neurons located in the subretrofacial area of the RVLM, approximately 1 to 1.7 mm rostral to obex. The bulbospinal projection from the RVLM is predominantly ipsilateral, and bulbospinal neurons do not appear to be organized within the RVLM in a manner indicating their segmental termination site. Eighty‐one percent (4%, n = 2) of the PNMT‐positive cells in the ipsilateral subretrofacial RVLM were retrogradely labeled after unilateral FG injections into multiple thoracic levels of the intermediolateral cell column (IML). Following, single level FG injections, the number of retrogradely labeled PNMT‐positive neurons in the subretrofacial RVLM decreased with injections in more caudal thoracic segments, indicating a heavier innervation of the upper thoracic IML by C1 neurons. PNMT‐negative neurons were the main component of the RVLM‐spinal population with 63 · 8% (n = 7) of the non‐PNMT‐containing neurons within the ipsilateral subretrofacial RVLM innervating all thoracic levels of the IML. The results indicate that both C1‐adrenergic and nonadrenergic neurons in the RVLM make a substantial contribution to the innervation of the IML.
The human transient subpial granular layer: An optical, immunohistochemical, and ultrastructural analysis
Authors: Gadisseux Jean‐François , Goffinet André M. , Lyon Gilles , Evrard Philippe 
Published: January 2005

AbstractThe cytological features, origin, migration, and fate of the subpial granular layer cells of the human embryonic cerebral cortex are studied with light and electron microscopy, Golgi impregnations, and immunocytochemical staining with the microtubule associated protein 2 and glial fibrillary acidic protein antibodies.Subpial granular layer (SGL) cells form a distinct neuronal population in the molecular layer, characterized by a small dark nucleus with abundant chomatin clumps and prominent nucleoli, and a lightly stained cytoplasm containing few organelles. Somata and processes of SGL cells are intensively stained with microtubule‐associated protein 2 antibody but do not express glial fibrillary acidic protein antibody.These cells apparently originate from the olfactory germinative zone. They follow two major strands from the olfactory subventricular zone to the subpial region. Subsequently, they migrate tangentially at the subpial level to all cortical regions, as is observed on Golgi and ultrastructural preparations.They constitute a transient population that penetrates the deep molecular layer and subsequently disappear from it. Several cytological features of these cells suggest an inward migration with growth of a radial process toward the cortical plate and subsequent nuclear translocation. The fate and the role of this new phylogenetic neuronal population has yet to be determined although the abundance of degenerating SGL cells in the deep molecular layer suggests at least partial degeneration.
The afferent and efferent connections of the nucleus submedius in the rat
Authors: Yoshida Atsushi , Dostrovsky Jonathan O. , Chiang Chen Yu 
Published: January 2005

AbstractThe afferent and efferent connections of the nucleus submedius (Sm) in the medial thalamus of the rat were examined. Injections of wheat‐germ agglutinin conjugated horseradish peroxidase (WGA‐HRP) into the Sm resulted in dense terminal labeling in the middle layers of the ipsilateral ventrolateral orbital cortex (VLO). Less dense labeling was also observed in the superficial and deep layers of VLO and in the medial part of the lateral orbital cortex (LO) and in the contralateral VLO. Retrogradely labeled neurons were observed primarily in the deep layers of VLO and the dorsal peduncular cortex (DP). Labeled neurons were also observed bilaterally, in the nucleus of the horizontal limb of the diagonal band, the lateral hypothalamus, the thalamic reticular nucleus (Rt), medial parabrachial nucleus (MPB), and the laterodorsal tegmental nucleus (LDT). Many labeled neurons were also observed in the trigeminal brainstem complex. Injections of Fluoro‐Gold (FG) into Sm resulted in a very similar distribution of retrogradely labeled neurons.Injections of WGA‐HRP and FG in the orbital cortex confirmed the ipsilateral Sm projection to VLO and suggested that the middle and deep layers of VLO receive a specific ipsilateral projection from the dorsal Sm and that the superficial layers receive a projection primarily from the ventral Sm. Injections of WGA‐HRP into the lateral hypothalamus, LDT, and MPB confirmed the retrograde labeling findings; the lateral hypothalamus was found to send a projection to the medial Sm, the LDT region to the ventromedial Sm and the MPB to the medial and dorsal Sm.These findings confirm and extend the results of previous studies in cat and rat indicating that Sm has a major and specific reciprocal connection with VLO. This finding, in conjunction with previous studies showing direct spinal and trigeminal inputs and the existence of nociceptive neurons in Sm and VLO, provides further support for a role of Sm in nociception.
Topographic organization of cortical and subcortical projections to posterior cingulate cortex in the cat: Evidence for somatic, ocular, and complex subregions
Authors: Olson C. R. , Musil S. Y. 
Published: January 2005

AbstractThe posterior cingulate area (CGp) of the cat consists of cortex on the exposed cingulate gyrus and in the adjacent ventral bank of the splenial sulcus. We have placed deposits of distinguishable fluorescent tracers at multiple restricted sites in CGp and have analyzed the distribution throughout the forebrain of neurons labeled by retrograde transport.Cortical projections to CGp arise (in approximately descending order of strength) from anterior cingulate cortex; prefrontal cortex and premotor areas including the frontal eye fields; visual areas including especially areas 7 and 20b; parahippocampal areas; insular cortex; somesthetic areas; and auditory areas. Corticocortical pathways are organized topographically with respect to the posterior‐anterior axis in CGp. Projections from prefrontal cortex and other areas with complex (as opposed to sensory, motor, or limbic) functions are concentrated posteriorly; projections from visual and oculomotor areas are concentrated at an intermediate level; and projections from areas with somesthetic and somatomotor functions are concentrated anteriorly.Thalamic projections to CGp arise from the anterior nuclei (AD, AV, and AM), from restricted portions of the ventral complex (VAd, VAm, and VMP), from discrete sectors of the lateral complex (LD, LPs, and LPm), from the rostral crescent of intralaminar nuclei (CM, PC, and CL), and from the reuniens nucleus. Projections from AM, VAd, LD, and LPs are spatially ordered in the sense that more ventral thalamic neurons project to more anterior cortical sites. Projections from AV and AD are stronger at more posterior cortical sites but do not show other signs of topographic ordering. Projections from LPm, CM, PC, CL, and RE are diffuse.We conclude (1) that cortical afferents of CGp derïve predominantly from neocortical areas including those with well established sensory and motor functions; (2) that limbic projections to CGp originate primarily in structures, including the hippocampus, which are associated with memory, as opposed to structures, including the amygdala, which are associated with emotional and instinctual behavior; and (3) that CGp contains subregions in which complex, ocular, or somatic afferents predominate. © 1992 Wiley‐Liss, Inc.
Expression of connexins in the developing olfactory system of the mouse
Authors: Miragall Fernando , Hwang Theng‐Khing , Traub Otto , Hertzberg Elliot L. , Dermietzel Rolf 
Published: January 2005

AbstractTo gain insight into the function of gap junctions' connexin43, connexin32 and connexin26 in a neural structure that retains neuronal turnover capacities throughout adulthood, the expression of these molecules has been investigated in the developing and adult olfactory system by immunocytochemical and biochemical methods.Connexin43 was detectable from the olfactory placode stage. During early embryonic development, the levels of connexin43 expression remained low. An increase in the expression of this connexin occurred perinatally. Expression of connexin43 became very high during the postnatal stages and adulthood. Electron microscopy (EM) immunocytochemistry of the olfactory system showed connexin43 expression in non‐neuronal cells. Strong regional differences in the expression of connexin43 in the olfactory epithelium were observed. No apparent relationship between connexin43 expression and turnover activity of olfactory neurons was detected. Western blots of olfactory tissues revealed the presence of three different isoforms of connexin43.Connexin32 was detected in the olfactory bulb at late postnatal stages including adulthood. Connexin32 was observed on some cells tentatively identified as oligodendrocytes.Connexin26 was localized onto leptomeninges. Some immunofluorescence was also obtained in the periglomerular region and in the subependymal layer of the bulb. Northern blot analysis revealed the presence of mRNA of connexin32 and connexin26 in the adult olfactory system. Our results substantiate the cell specific expression of these three types of connexins and they document the primacy of connexin43 in olfactory tissues. Moreover, our findings indicate that although expression of connexin43 in the olfactory system is developmentally regulated, it is not directly associated with the neuronal cell turnover of the olfactory epithelium. © 1992 Wiley‐Liss, Inc.
Nerve ring of the hypostome in Hydra. I. Its structure, development, and maintenance
Authors: Koizumi Osamu , Itazawa Motoko , Mizumoto Hiromi , Minobe Sumiko , Javois Lorette C. , Grimmelikhuijzen Cornelis J. P. , Bode Hans R. 
Published: January 2005

AbstractThe anatomy and developmental dynamics of the nerve ring in the hypostome of Hydra oligatis were examined immunocytochemically with an antiserum against a neuropeptide and with neuron‐specifie monoclonal antibodies. The nerve ring is unique in the mesh‐like nerve net of hydra. It is a distinct neuronal complex consisting of a thick nerve bundle running circumferentially at the border between the hypostome and tentacle zone. Immunostaining showed that the nerve ring was heterogeneous and contained at least four different subsets of neurons. During head regeneration and budding, the nerve ring appeared only after the nerve net of ganglion and sensory cells had formed. Every epithelial cell is continuously displaced with neurons toward either head or foot in an adult hydra. However, the ectoderm in the immediate vicinity of, and including, the nerve ring constitutes a stationary zone that is not displaced. Tissue immediately above this zone is displaced toward the tip of the hypostome, while tissue below is displaced along the tentacles. Correspondingly, the production of new neurons in the ring as measured by their differentation kinetics is much slower than in surrounding areas. Thus, the nerve ring is static and stable in contrast to the dynamic features of the nerve net of hydra. © 1992 Wiley‐Liss, Inc.
Neuronal and synaptic composition of the mediodorsal thalamic nucleus in the rat: A light and electron microscopic golgi study
Authors: Kuroda Masaru , López‐Mascaraque Laura , Price Joseph L. 
Published: January 2005

AbstractThe distribution and dendritic domain of neurons in each segment of the mediodorsal thalamic nucleus (MD) have been studied in the rat with the Golgi technique. In addition, a combined Golgi method‐electron microscopic (Golgi‐EM) study was undertaken to determine the distribution of morphologically distinct synapse types along the dendrites of individual identified neurons in MD.All the subdivisions or “segments” of MD (medial, central, lateral) contained both stellate and fusiform cells. The dendritic domain of both types of cells was predominantly restricted to the same segment of MD that contained the cell body of the neuron. Typical stellate neurons were found near the center of each segment, with radiating dendrites that extended to but not across the boundaries of the segment. Fusiform cells were usually located close to the segmental or nuclear boundaries and tended to have dendrites oriented parallel to those borders; again, the dendrites tended not to extend across borders between segments or at the outer edge of MD. In the medial segment of MD many fusiform cells had especially bipolar dendritic configurations, generally with a dorsoventral orientation. Because no small neurons were identified that might correspond to thalamic interneurons, all the impregnated cells in MD are presumed to be thalamocortical projection neurons. These results indicate that cells and their major dendrites are confined to a single segment of MD, with little dendritic overlap across segmental or nuclear borders. The segments of MD may therefore be considered to be relatively independent subnuclei.The distribution of the four types of synapses previously identified in MD (Kuroda and Price, J. Comp. Neurol., 303:513–533, 1991) was determined along several identified dendrites studied with the Golgi‐EM method. Primary dendrites were contacted mostly by large axon terminals, including both large, round vesicle (LR) terminals and large, pleomorphic vesicle (LP) terminals, as well as a few small to medium sized terminals with pleomorphic vesicles (SMP). No small terminals with round vesicles (SR terminals) were observed to make synapses with primary dendrites. Secondary and tertiary dendrites received synapses from all types of axon terminals. Higher order dendrites were contacted predominantly by SR boutons, but they also carried some LR and SMP terminals. In addition, SMP boutons were often found to form symmetric contacts with cell somata. © 1992 Wiley‐Liss, Inc.
Direct observations of synapses between L‐glutamate‐immunoreactive boutons and identified spinocervical tract neurones in the spinal cord of the cat
Authors: Maxwell D. J. , Christie W. M. , Brown A. G. , Ottersen O. P. , Storm‐Mathisen J. 
Published: January 2005

AbstractFour spinocervical tract cells in lumbosacral spinal cords of adult cats were physiologically characterized and intracellularly labelled with horseradish peroxidase. The neurones were examined with a light microscope and reconstructed. Selected regions were chosen for ultrastructural analysis. Thin sections were treated to reveal the presence of L‐glutamate by using the postembedding immunogold method. Two antisera, which specifically recognise the presence of fixed glutamate in tissue, were used in the study. Somata, proximal, and distal dendrites of all four neurones received synaptic contacts from boutons which displayed an obvious immunogold reaction. These boutons formed between 35% and 48% of all synaptic contacts onto spinocervical tract cells. Glutamate‐enriched boutons were associated with gold particle densities which were 2–3 times greater than the average densities associated with the surrounding neuropil. Their profiles had a mean diameter of 1.68 μm, contained round agranular synaptic vesicles, and formed asymmetrical synaptic junctions. However, not all boutons displaying these characteristics were enriched with glutamate.Immunogold studies of alternate thin sections, which were incubated with glutamate or GABA antiserum, demonstrated that synaptic boutons on spinocervical tract cells were either enriched with GABA or with glutamate and formed two separate populations which had distinct morphological characteristics. GABA‐containing boutons contained irregularly shaped agranular vesicles and formed symmetrical synaptic junctions, whereas glutamate‐enriched boutons corresponded to those described above. A further population of boutons, containing highly flattened vesicles, was not immunoreactive for GABA or glutamate.The evidence supports the idea that much of the excitatory transmission into the SCT is mediated by L‐glutamate. © 1992 Wiley‐Liss, Inc.
Direct and indirect “cortico”‐rubral and rubro‐cerebellar cortical projections in the pigeon
Authors: Wild J. Martin 
Published: January 2005

AbstractIn birds the red nucleus is the most rostral cell group in the brain having projections to all levels of the spinal cord (Cabot et al., Prog. Brain Res., 57:79–108, 1982), but its sources of afferents are incompletely known. In order to determine these, a series retrograde and anterograde tracing experiments was carried out, largely with cholera toxin B‐chain conjugated to horseradish peroxidase. The results show that a sparse and diffuse projection to the red nucleus arises from deep regions of the hyperstriatum accessorium (HA) of the anterior Wulst, and that a much more dense projection arises from the caudal part of the nucleus principalis precommissuralis and the medial part of the medial spiriform nucleus (SpMm). These last two sources were themselves shown to receive a substantial projection from HA of the anterior Wulst.The red nucleus was also shown to project upon the cerebellar cortex of lobule VI, and SpM upon the cerebellar cortex of lobules VI through IX (Karten and Finger, Brain Res., 102:335–338, 1976; Clarke, J. Comp. Neurol., 174:535–552, 1977). Double retrograde labelling experiments with fluorescein and rhodamine labelled latex microspheres injected into the cerebellar cortex and spinal cord showed that the rubrocerebellar cortical neurons are a different population from, although intermixed with, the rubrospinal neurons. © 1992 Wiley‐Liss, Inc.