bluuebunny/crossref_metadata_2025_split huggingface dataset:
Morphology of physiologically identified slowly adapting lung stretch receptor afferents stained with intra‐axonal horseradish peroxidase in the nucleus of the tractus solitarius of the cat. I. A light microscopic analysis
Authors: Kalia Madhu , Richter Diethelm 
Published: May 2005

AbstractThe present series of experiments was designed to study the organization of preterminai processes and synaptic boutons of single physiologically identified slowly adapting receptor (SAR) pulmonary stretch afferent fibers. Intra‐axonally injected horseradish peroxidase‐wheat germ agglutinin (HRP‐WGA) conjugate was used as the label. In the first paper, we describe the pattern of arborization of axon collaterals from single physiologically identified SAR afferent fibers evident in the various subnuclei of the nucleus of the tractus solitarius (nTS). In the second paper, details are presented regarding the ultrastructure of these synaptic boutons and axon collaterals.A number of significant findings resulted from this study: (1) A single lung stretch SAR afferent fiber arborized over a considerable distance rostrocaudally in the brain stem (1,700–2,100 μm). (2) A single lung stretch SAR afferent fiber terminated as hundreds of bouton terminals (650–1,180). (3) There was a remarkable consistency in the subnuclei of the nTS that received these terminal arborizations of SAR afferents. (4) The ventral (vnTS), intermediate (nI), ventrolateral (vInTS), and interstitial (ni) subnuclei of the nTS were the only regions of the nTS receiving bouton terminals of SAR afferent fibers. (5) Under the light microscope the pattern of termination of SAR afferents was similar in all the axons studied in this series. (6) The injected parent axon in each case could be followed in the TS at all levels and remained consistent with regard to position and orientation and could be traced rostrally to levels as far as 3.5 mm rostral to the obex whereas the region of terminal arborization was located around 1.7–2.1 mm rostral to the obex. This pattern indicates that a single lung stretch SAR afferent fiber descends caudally upon entering the nTS. In the cat vagal afferent fibers are known to enter the medulla at levels between 0.5 mm and 3.2 mm rostral to the obex (Kalia and Mesulam, '80a).The results of the light microscopic analysis presented in this article indicate that lung stretch (SAR) afferents from the lungs and tracheobronchial tree have distinctly localized patterns of distribution in the nTS. In addition, these findings support the concept that representation of pulmonary afferents in the medulla is constituted by a differentiated distribution of nerve terminals in the various subnuclei of the nTS. Modality‐specific localization (SAR afferents in this case) appears to be predominant in the n'1'S. The widespread rostrocaudal distribution of the terminal field of a single lung stretch SAR afferent is remarkable. In addition, the finding that the terminals of different SAR afferents are localized in only a few subnuclei of the nTS suggests that specificity exists in this afferent system which could provide the morphological substrate for focussed physiological effects.
Morphology of physiologically identified slowly adapting lung stretch receptor afferents stained with intra‐axonal horseradish peroxidase in the nucleus of the tractus solitarius of the cat. II. An ultrastructural analysis
Authors: Kalia Madhu , Richter Diethelm 
Published: May 2005

AbstractThe nucleus of the tractus solitarius is a site for termination of primary afferents originating from a variety of visceral receptors. The localization of bouton terminals of slowly adapting lung stretch (SAR) afferent fibers originating from the tracheobronchial tree have been described in the companion paper (Kalia and Richter, '85). The most conspicuous finding regarding the location of SAR terminals is that they are concentrated within specific subnuclear groups of the nucleus of the tractus solitarius (nTS) and are distributed widely in the rostrocaudal plane of the medulla oblongata. These light microscopic features have provided us with valuable information with regard to the organization of visceral afferents in the central nervous system. The synaptic profiles formed by the 476 bouton terminals of these HRP‐labeled afferents have been described in this paper in serial thin sections. All of the bouton terminals examined under the electron microscope were found to contain round synaptic vesicles. Synaptic boutons (1.0–3.0) /μm in diameter were usually of the en passant variety and made contact with different structures depending upon the subnucleus which was examined. In the ventral (v) and the ventrolateral (vl) subnuclei of the nTS, asymmetrical (type I) synaptic contacts containing round, clear synaptic vesicles of 35–50 ion μm in diameter were found and these contacts were made with (1) the soma of cell bodies located in that subnucleus; (2) spiny dendrites in that nucleus; (3) vesicle‐containing axon terminals that were presynaptic to the HRP‐labeled bouton terminal; and (4) vesicle‐containing dendrites in which the HRP profile was presynaptically located. The terminal axon remained my‐elinated till the last 1 μm before the bouton terminal was formed. There was no distinct, unmyelinated portion of the terminal axon. The synaptic bouton received axon‐axonal synapses from unlabeled bouton terminals containing round, clear vesicles.This is the first report of the localization of these afferent fibers as well as of the regional variations in the ultrastructure of boutons of physiologically identified terminals. It appears likely that the lung stretch afferent fibers, by having axon‐axonal as well as axon‐somatic contact in the ventral, ventrolateral, and intermediate subnuclei of the nTS, can interact in a variety of different ways in this region. The significance of these features in relation to the precise influence of respiratory afferents on central respiratory mechanisms needs to be evaluated further.
The efferent projections from the reticular formation and the locus coeruleus studied by anterograde and retrograde axonal transport in the rat
Authors: Jones Barbara E. , Yang Tian‐Zhu 
Published: May 2005

AbstractFollowing injections of [3H]leucine into the formatio reticularis gigantocellularis (Rgc), reticularis pontis caudalis (Rpc), reticularis pontis oralis (Rpo), reticularis mesencephali (Rmes), or the locus coeruleus (LC) of the rat, autoradiographic study revealed prominent reticuloreticular projections from all areas and secondary projections onto cranial nerve motor nuclei from most areas within the brain stem. Common long descending projections extended the full length of the spinal cord terminating in the ventromedial ventral horn and intermediate zone and more sparsely in the base of the dorsal horn and (particularly from Rgc) the region of the motoneurons. Common long ascending projections extended into the forebrain via Forel's tegmental fascicles. A dorsal branch of fibers innervated the intralaminar and midline nuclei of the thalamus. The major fiber system continued forward through Forel's fields and ascended into the pallidum from Rpo, Rmes, and LC and into the neostriatum from Rmes and LC. Fascicles from all areas also ascended in the medial forebrain bundle through the lateral hypothalamus to the lateral preoptic area, substantia innominata, and nuclei of the diagonal band. From Rpo, Rmes, and LC, fibers continued forward to reach the cerebral cortex, where the innervation was sparse and discrete from Rpo and Rmes but moderate and ubiquitous from LC.Retrograde transport of true blue and/or nuclear yellow revealed inverse gradients along the brain stem longitudinal axis of interdigitated cells respectively projecting caudally into the spinal cord (with the greatest number of cells in Rgc, Rpc, and Rpo) and rostrally into the diencephalon (with the greatest number of cells in Rmes and LC), with very few cells projecting both to the spinal cord and the diencephalon. From the basal forebrain, a large number of reticular and LC cells were retrogradely labelled, whereas from the frontal cortex, a much smaller number of reticular cells was labelled. These results document the widespread efferent projections from the reticular formation and overlapping, yet more extensive, projections from the LC.
The cerebellar and vestibular nuclear complexes in the turtle. I. Projections to mesencephalon, rhombencephalon, and spinal cord
Authors: Künzle H. 
Published: May 2005

AbstractCerebellar and vestibular projections were investigated in the turtle Pseudemys scripta elegans following injection of 35S‐methionine into the cerebellar and vestibular nuclear complexes at various locations.Fibers arising from the cerebellar nuclei were traced via the cerebellar commissure to the contralateral vestibular nuclear complex (particularly the n. vestibularis inferior and n. vestibularis ventrolateralis) and caudal rhombencephalic tegmentum. Ascending projections crossing the midline in the ventral isthmomesencephalic tegmentum terminated in the contralateral red nucleus and nuclei of the fasciculus longitudinalis medialis (flm).Vestibular projections ascending mainly via the flm terminated in the nuclei of the flm, the nuclei of the posterior commissure, and particularly the extraocular motor nuclei. Vestibulo‐ocular projections arising from the rostral vestibular nuclear complex were almost exclusively ipsilateral; those from the caudal vestibular nuclear complex were bilateral. Evidence for a topographic organization of the projections to the trochlear and oculomotor nuclei was also obtained. There were some vestibular projections to the contralateral rhombencephalic tegmentum and n. vestibularis inferior. Spinal projections coursing within the ipsilateral ventral descending tract and the ipsilateral fasciculus longitudinalis medialis were found to arise from both rostral and caudal vestibular regions. The caudal vestibular nuclear complex in addition gave rise to fibers descending in the contralateral fasciculus longitudinalis medialis. Evidence for the existence of labeled fibers crossing at spinal levels was also obtained. Vestibulospinal terminations appeared restricted to the ventral horn.
The cerebellar and vestibular nuclear complexes in the turtle. II. Projections to the prosencephalon
Authors: Künzle H. 
Published: May 2005

AbstractProsencephalic projections from the cerebellar and vestibular nuclear complexes in the turtle Pseudemys scripta elegans were investigated with anterograde tracing. Following injections of 35S‐methionine at various locations within the cerebellar and vestibular nuclear complexes, labeled ascending fibers were found to arise from the lateral cerebellar and the rostral (superior and/or dorsolateral) vestibular nuclei. The great majority of these fibers coursed within the ipsilateral ascending periventricular tract.There were possible terminations in the hypothalamosuprapeduncular region, the ovalis‐complex, and the nucleus commissuralis anterior, but scarcely any indication of terminal labeling within the dorsal thalamus. The labeled fibers, however, continued rostralward, entered the lateral forebrain bundle, and terminated in the anterior dorsal ventricular ridge—in all but one case, exclusively ipsilaterally. The terminal area within the lateral division (referred to as area L) of the anterior dorsal ventricular ridge was sharply delimited, being situated ventrolateral to the visually oriented area D of the anterior dorsal ventricular ridge (Balaban and Ulinski, '81), medial to the lateral cortex, and ventral to the pallial thickening (motor pallium of Johnston, '16).The findings are compared with related ones in mammals, particularly those pertaining to telencephalic somatosensorimotor regions and their interactions with the vestibular nuclear complex and the cerebellum.
Immunohistochemical study of subclasses of olfactory nerve fibers and their projections to the olfactory bulb in the rabbit
Authors: Mori Kensaku , Fujita Shinobu C. , Imamura Kazuyuki , Obata Kunihiko 
Published: May 2005

AbstractThe organization of the olfactory nerve projection to the olfactory bulb was studied immunohistochemically in the rabbit by using monoclonal antibodies (MAbs). Out of 42 MAbs raised against the homogenate of the olfactory bulb, two types of MAbs that strongly stained the olfactory nerve fibers (axons of olfactory receptor cells) were selected and their staining patterns were analysed in detail. MAbs of one type (represented by MAb R2D5) specifically labeled all olfactory receptor cells in the nasal epithelium and all olfactory nerve fibers and their terminal portions in the bulb.The other type of MAbs (represented by MAb R4B12) recognized only a subgroup of olfactory nerve fibers. The R41312‐positive fibers were distributed over the ventrolateral areas but not in the dorsomedial areas of the epithelium. Similarly in the bulb, the R41312‐positive fibers terminated in the glomeruli in the ventrolateral and the caudal regions but not in the dorsomedial region. These results demonstrate for the first time the cellular heterogeneity among olfactory receptor neurons at the molecular level. The segregated distribution of the subtypes of olfactory receptor cell axons both in the epithelium and the bulb indicates a defined topographical organization of the olfactory nerve projection. These results also suggest a functional division between dorsomedial and ventrolateral areas both in the epithelium and the bulb.
Wide‐spreading terminal axons in the inner plexiform layer of the cat's retina: Evidence for intrinsic axon collaterals of ganglion cells
Authors: Dacey Dennis M. 
Published: May 2005

AbstractExtracellular, iontophoretic injections of horseradish peroxidase (HRP) were made directly into the cat's retina. The retinas were processed with the cobalt‐enhanced diaminobenzidine method and prepared as whole mounts. These retinas reveal HRP‐filled axons that extend widely and terminate within the inner plexiform layer. The axons are morphologically distinct from ganglion and amacrine cell dendritic trees that were retrogradely labelled from the same injection sites.The axons are long and straight, approximately 1 μm in diameter, and in some cases can be traced for several millimeters in the inner plexiform layer. Each axon gives rise to many short, terminal branches that extend, on average, 100 μm from the parent axon and bear clusters of boutons. The terminal branches are widely spaced so that the bouton clusters are distributed in small, isolated patches along the length of the axon. Bouton clusters vary in size and contain from two to over 100 loosely arranged boutons. Single boutons are frequently large, up to 3 μm in diameter.In one case a terminal axon was traced to its origin from the parent axon of an HRP‐filled ganglion cell. It is suggested, therefore, that these axons are intrinsic to the retina and originate as primary collaterals of ganglion cells.
Catecholamine innervation of the caudal spinal cord in the rat
Authors: Schrøder Henrik Daa , Skagerberg Gunnar 
Published: May 2005

AbstractBy means of the aluminum‐formaldehyde (ALFA) fluorescence technique for monoamine visualization the distribution of catecholamines was studied in the caudal spinal cord, particularly in relation to motoneurons innervating pelvic structures.In the lumbosacral cord all parts of the spinal gray matter were found to contain catecholamines. In the dorsal horn the most intense fluorescence was seen in the superficial layers. The motoneuron neuropil exhibited the most prominent catecholamine‐fluorescence of the ventral horn layers. In the sixth lumbar segment, which contains the motor nuclei that innervate the pelvic striated muscles as well as one innervating muscles in the lower limb, a differential distribution of the density of catecholamine fluorescence was presented by the individual nuclei.The catecholamine fibers in the motoneuron neuropil were seen closely surrounding the motoneuron somata, suggesting the existence of axosomatic contacts, and by utilizing the fluorescent retrograde tracer True Blue in combination with the ALFA method tentative axosomatic noradrenergic synapses on identified neurons innervating small striated pelvic muscles could be visualized in the light microscope.In the intermediate gray the intermediolateral nucleus in thoracic and upper lumbar segments was the most heavily innervated area, followed by the medial lumbar sympathetic group, which contains the majority of the sympathetic preganglionic neurons innervating the pelvic organs. The parasympathetic intermediolateral nucleus in the upper sacral segments received a catecholamine innvervation of moderate density.The catecholamine innervation pattern is discussed in relation to the patterns of other putative transmitters. The distribution of catecholamine fluorescence in relation to nuclei that control the pelvic organs differs from the arrangement of other transmitters in this region. The complexity of the innervation of the pelvic organs and their related striated muscles is thus further stressed.
The dorsal cochlear nucleus of the mouse: A light microscopic analysis of neurons that project to the inferior colliculus
Authors: Ryugo D. K. , Willard F. H. 
Published: May 2005

AbstractIn the mouse dorsal cochlear nucleus (DCN), all members of a distinct class of large multipolar neurons were shown to project to the contralateral inferior colliculus by using retrograde horseradish peroxidase techniques. Typically, these multipolar neurons have the largest cell bodies in the nucleus and are distributed in layers II, III, and IV. Each contains a round, pale nucleus with a prominent nucleolus and conspicuous Nissl bodies. In Golgi preparations, however, two types of large cells could be distinguished on the basis of dendritic characteristics. Pyramidal cells form relatively flattened, slablike dendritic fields whose alignment contributes to the laminar organization of the DCN. They represent 75–80% of the large cell population and are found in layer II and the superficial region of layer III. Giant cells represent the other type of large multipolar neuron and are distributed in the deeper regions of layer III and in layer IV. Their ellipsoidal dendritic fields are formed by long and relatively unbranched dendrites that project across the laminae. The differences in dendritic morphology imply that each cell class segregates its afferent input in distinct ways and subserves different auditory functions.
Topographic representation of visceral target organs within the dorsal motor nucleus of the vagus nerve of the pigeon Columba livia
Authors: Katz David Miles , Karten Harvey J. 
Published: May 2005

AbstractOur previous work (Katz and Karten, '83a J. Comp. Neurol. 217:31–46) demonstrated that the dorsal motor nucleus of the vagus nerve (DMN complex) in the pigeon is composed of cytoarchitecturally distinct subnuclei that are distinguished by the size, shape, position, and cytochemical characteristics of their constituent neurons. In view of the diversity of target organs innervated by the vagus nerve, we sought to determine whether the subnuclear heterogeneity of the DMN complex is related to the pattern of target innervation. To test this possibility, retrograde tracing techniques were used to define the subnuclear localization of vagal motoneurons that innervate individual vagal target organs.The distribution of horseradish peroxidase (HRP)‐labeled motoneurons within the DMN complex was studied following application of HRP to the cut central end of individual vagal nerve branches and after injection of the tracer into vagal target tissues. In addition, we examined the distribution of acetylcholinesterase depletion within the DMN complex following transection of individual vagal branches.Our data demonstrate that individual vagal target organs have discrete and topographic representations within cytoarchitecturally distinct subnuclei of the DMN complex. Therefore, in the pigeon, the subnuclear distribution of vagal motoneurons plays a critical role in the organization of descending vagal motor pathways. Segregation of visceral representations within the DMN complex may provide a mechanism for organizing functionally diverse afferent inputs to target‐specific populations of vagal motoneurons.
Neurogenesis of the cat's primary visual cortex
Authors: Luskin Marla B. , Shatz Carla J. 
Published: May 2005

AbstractThe 3H‐thymidine method of birth‐dating was used to determine when the cells belonging to each of the principal cellular layers of the cat's primary visual cortex are generated. In order to detect systematic differences in the position of radioactively labeled cells following 3H‐thymidine administration at different prenatal ages, a geometric method was devised to represent the distribution of labeled cells in the form of depth histograms. Results show that visual cortical neurogenesis occurs largely during the second half of gestation between embryonic day 31 (E31) and E57. Cells of layer 6 are generated early, between E31 and E38, whereas cells destined for successively more superficial layers are generated at progressively later times. Layer 4 cells, the principal targets of geniculocortical afferents, are generated between E37 and E44. In addition, a special population of cells embedded in the white matter below layer 6 was found to be produced throughout the week‐long period immediately prior to the onset of layer 6 neurogenesis. Overall, this radial pattern of cortical neurogenesis closely resembles the inside‐first, outside‐last, spatiotemporal sequence of development described for the monkey's primary visual cortex (Rakic, '74).In addition to finding this pronounced gradient in the radial dimension, we were also able to detect a less pronounced gradient along the tangential dimension: neurons destined for any given layer in the anterior part of the cortex (inferior visual, field representation) are generated slightly in advance of neurons destined for more posterior regions (superior visual field). However even our more quantitative histogram analysis failed to reveal a mediolateral (central to peripheral visual field) gradient within area 17.In the cat, layers 6, 5, and 4 each take about a week to be generated, although their total cell numbers and packing densities differ in the adult. About 2 weeks are required to produce the cells of layers 2 and 3 combined. Furthermore, we found that neurons belonging to different layers and different morphological classes can be generated simultaneously. This suggests that the identity of a cortical neuron is not solely a function of the time of neurogenesis.