bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nuclear clefting in dorsal root ganglion neurons: A response to whole body vibration
Authors: McLain Robert F. , Weinstein James N. 
Published: May 2005

AbstractNormal adult rabbits were studied in a whole body vibration model which simulates the type of environmental exposure associated with vibration‐induced low back pain. This model has previously been shown to induce changes in pain‐related neuropeptides in the dorsal root ganglion. Following two weeks of daily exposure to whole body vibration, dorsal root ganglia were excised from control and vibrated rabbits and prepared for ultrastructural evaluation. Of over 1,200 cells sampled, 190 appropriately sectioned cells were analyzed: 32 from immobilized controls, 44 from normal controls, and 114 from vibrated animals. Analysis of nuclear contours revealed more prevalent and more extensive clefting of the nuclear membrane in vibrated cells. The membrane lining these clefts was traversed by numerous pores; density of these pores was 46% greater than in adjacent nonclefted segments (p <.001). Number of clefts per nucleus was increased by 39% in vibrated animals. Cleft area represented 1.19% of nuclear area in vibrated cells compared to 0.74% in controls (p <.001). Numerous mitochondria and free ribosomes and abundant rough endoplasmic reticulum were located within the cleft spaces of vibrated cells. Pores in the cleft membrane appeared normal, supporting the conclusion that the clefts are structural alterations rather than fixation or sectioning artifacts.Changes in dorsal root ganglion neuropeptides seen in previous studies of vibrated animals may result from increased or redirected cellular synthesis. Ultrastructural changes seen in these vibrated dorsal root ganglion neurons are consistent with such an alteration in metabolism and could reflect increased synthesis of pain‐related neuropeptides. © 1992 Wiley‐Liss, Inc.
Spatial representation of frequency‐modulated signals in the tonotopically organized auditory cortex analogue of the chick
Authors: Heil Peter , Scheich Henning 
Published: May 2005

AbstractFor auditory communication, many birds, including domestic chicks, use a variety of frequency‐modulated (FM) sounds. As a first approach to the spatial representation of such sounds in the central auditory system, we have analyzed 2‐deoxyglucose (2DG) patterns that were produced by FM stimuli in the tonotopic map of the auditory forebrain area (field L/hyperstriatum ventrale complex) of domestic chicks. Linear FM signals, varying in the depth and range of modulation, and in the direction and rate of the frequency change, were tested. Also included were signals designed to mimic species‐specific FM calls. All FM stimuli activated those regions of the map in which frequencies contained in the stimulus spectra were tonotopically represented. However, frequency and amplitude of the FM spectra were not faithfully reproduced by activation of the complete corresponding tonotopic space. FM signals that differed only in the direction of modulation, and therefore had identical long‐term spectra, induced maximum 2DG activation at different locations of the tonotopic gradient. FM signals that differed in the rate of change of frequency produced maxima of 2DG uptake at different positions along an isofrequency dimension of the map. These results suggest that the direction of modulation may be represented in a complex fashion along the tonotopic axis of the structure, whereas the rate of change of frequency may be represented along an isofrequency dimension. None of the experiments provided evidence of FM‐selective regions within the auditory forebrain complex. However, numerous telencephalic areas, in addition to the primary auditory area, were strongly activated in chicks stimulated with artificial “species‐specific” FM signals. These areas could be involved in the processing of biologically relevant stimuli, requiring attention, recognition, and interpretation of the signals. © 1992 Wiley‐Liss, Inc.
Lucifer yellow, retrograde tracers, and fractal analysis characterise adult ferret retinal ganglion cells
Authors: Wingate Richard J. T. , Fitzgibbon Tom , Thompson Ian D. 
Published: May 2005

AbstractThe dendritic morphology of retinal ganglion cells in the ferret was studied by the intracellular injection of lucifer yellow in fixed tissue. Ganglion cells were identified by the retrograde transport of red or green fluorescent microspheres that had been injected into different target nuclei, usually the lateral geniculate nucleus or superior colliculus. This approach allows the comparison of dendritic morphologies of ganglion cells in the same retina with different central projections and also identifies cells with branching axons. The digitised images of dendritic arbors were analysed quantitatively by a variety of measures. Dendritic complexity was assessed by calculating the fractal dimension of each arbor. The ferret has distinct alpha, beta, and gamma morphological classes of cells similar to those found in the cat. The gamma cell class was morphologically diverse and could be subdivided into “sparse,” “loose,” and “tight” groups, reflecting increasing dendritic complexity. Whereas the beta cell projection was limited to the lateral geniculate nucleus alone, alpha and gamma cells could project to either or both nuclei. Retinal ganglion cells labelled from the pretectal nuclei formed a morphologically distinct class of retinal ganglion cells. The ipsilateral projection lacked alpha cells and the most complex, “tight” gamma cells. However, ipsilaterally projecting “loose” gamma cells overlapped alpha cells in both soma and dendritic dimensions. Different morphological classes of retinal ganglion cells hence show characteristic axon behaviour both in their decussation at the chiasm and in which targets they innervate. Fractal measures were used to contrast variation within and between these identified classes. © 1992 Wiley‐Liss, Inc.
Long distance directed axonal growth from human dopaminergic mesencephalic neuroblasts implanted along the nigrostriatal pathway in 6‐hydroxydopamine lesioned adult rats
Authors: Wictorin K. , Brundin P. , Sauer H. , Lindvall O. , Björklund A. 
Published: May 2005

AbstractDissociated ventral mesencephalon of 6 to 8‐week‐old human embryos were implanted by stereotaxic injection at different sites along the nigrostriatal pathway in adult rats, previously subjected to a 6‐hydroxydopamine lesion of the intrinsic mesotelencephalic dopamine pathways. The recipients were immunosuppressed by daily injections of cyclosporin A to prevent rejection. At 13–20 weeks after transplantation, the implanted human neurons and their associated fiber outgrowths were visualized with a species‐specific antibody recognizing human, but not rat, intermediary neurofilaments (HNF). From implants placed in the host rostral mesencephalic region, HNF‐positive axonal projections were, seen to extend in large numbers rostrally along the medial forebrain bundle and the internal capsule, and ramify within the caudate putamen, the ventral striatum and the amygdaloid nuclei (a distance of about 5–6 mm), and more sparsely in the frontal cortex and the olfactory bulb (a distance of about 10 mm). From implants placed in the internal capsule, abundant HNF‐positive axons extended in the rostral, but not caudal, direction along the myelinated fiber bundles into the caudate putamen and the ventral striatum. Tyrosine hydroxylase (TH) immunohistochemistry revealed that the vast majority of the rostrally projecting HNF‐positive axons were also TH‐positive, and that the graft‐derived axons gave rise to dense TH‐positive terminal networks, above all in large areas of the previously denervated caudate putamen. From control implants of cortical neuroblasts, axonal projections were seen along the medial forebrain bundle and the internal capsule, but the axons were TH‐negative and showed only sparse projections to the striatal areas. Instead, dense projections were seen, e.g., in the frontal cortex.The results demonstrate a remarkable ability of human mesencephalic neuroblasts to extend axons along the trajectories of the nigrostriatal and mesolimbocortical pathways to reach and innervate the principal striatal and limbic target areas in the forebrain. This shows that the basic requirements for the formation of long axonal pathways may be present in the adult mammalian central nervous system (CNS) at least for certain types of projection neurons. Furthermore, it implies that the developing human neuroblasts can escape the inhibitory features known to be present along myelinated growth trajectories in the adult mammalian brain. In addition, the present approach may offer new possibilities for functional neural grafting in the rat Parkinson model, since transplanted nigral neurons placed in their natural position within the rostral mesencephalon could provide an anatomically and functionally more integrated system than the standard model with ectopically placed intrastriatal nigral grafts. © 1992 Wiley‐Liss, Inc.
The shell region of the nucleus ovoidalis: A subdivision of the avian auditory thalamus
Authors: Durand Sarah E. , Tepper James M. , Cheng Mei‐Fang 
Published: May 2005

AbstractThe connectivity of a region surrounding the established thalamic auditory nuclei, n. ovoidalis (Ov) and n. semilunaris parovoidalis (SPO), was explored in the ring dove by using the anterograde tracers, Phaseolus vulgaris leucoagglutinin (PHAL) and biocytin, and the retrograde tracer, fluorogold. The Ov‐SPO surround received a projection from a cell group along the interface of the auditory midbrain and the n. intercollicularis, as revealed with PHAL and biocytin, and was composed of neurons exhibiting a common morphology. These features and the presence of overlapping projections from different portions of the Ov‐SPO surround suggest that this region comprises a functionally discrete area, which we term the Ov shell. Single unit recording within the shell established the existence of acoustically responsive units.Both PHAL and fluorogold labeling revealed a robust projection from the Ov shell to the caudomedial hypothalamus. Major telencephalic projections of the shell terminated within the ventral paleostriatal complex, “end‐zones” of the field L, the caudomedial hyperstriatum ventrale, and regions immediately dorsal and lateral to the auditory neostriatum. Except for a portion of the shell bordering medial ovoidalis, PHAL injections into the shell also labeled fibers within the caudolateral neostriatum and along the lateral neostriatal rim.The connectivity of the Ov shell suggests that this region may integrate auditory pathways with brain regions associated with endocrine mediated behavior. In addition, the shell may constitute a source of converging input to several levels of central auditory pathways. © 1992 Wiley‐Liss, Inc.
Development of the olivocerebellar projection in the rat: II. Matching of the developmental compartmentations of the cerebellum and inferior olive through the projection map
Authors: Wassef Marion , Cholley Béatrice , Heizmann Claus W. , Sotelo Constantino 
Published: May 2005

AbstractA transient biochemical parcellation has been observed by immunocytochemical methods, during the perinatal development of both the inferior olive and the cerebellum. In the present study, we sought a relationship between this developmental compartmentation and the organization of the olivocerebellar projection. In the inferior olive, a transient parvalbumin immunoreactivity restricted to the dorsal cap of the medial accessory olive is observed around birth. The climbing fiber projection of the dorsal cap was identified in the cerebellum of newborn rats based on its parvalbumin immunoreactivity. The pattern of this projection, restricted to lobules IX and X of the vermis, and to the flocculus, is indistinguishable from that of the adult medial accessory olive, which was previously described from axonal tracing experiments. The parvalbumin immunoreactive climbing fibers were followed between birth and postnatal day 7. In the caudal vermis, Purkinje cell subpopulations can be identified between embryonic day 20 and postnatal day three, on the basis of their differential immunostaining with an antibody directed against a specific peptide, PEP 19. In lobule X, the parvalbumin immunoreactive climbing fibers form two sagittal bands on each side of the midline, one medial and one lateral. The medial parvalbumin immunoreactive climbing fiber band is coextensive with a PEP 19 negative Purkinje cell cluster, indicating a clear relationship between the biochemical parcellations of the cerebellum and inferior olive. © 1992 Wiley‐Liss, Inc.
Immunocytochemical survey of putative neurotransmitters in taste buds from Necturus maculosus
Authors: Welton Joan , Taylor Randy , Porter Angela J. , Roper Stephen D. 
Published: May 2005

AbstractTo investigate synaptic mechanisms in taste buds and collect information about synaptic transmission in these sensory organs, we have examined taste buds of the mudpuppy, Necturus maculosus for the presence of neurotransmitters and neuromodulators. Immunocytochemical staining at the light microscopic level revealed the presence of serotonin‐like and cholecystokinin‐like (CCK) immunoreactivity in basal cells in the taste bud. Nerve fibers innervating taste buds were immunoreactive for vasoactive intestinal peptide‐like (VIP), substance P‐like, and calcitonin gene‐related peptide‐like (CGRP) or compounds closely related to these substances. Immunoreactivity for tyrosine hydroxylase (TH) and choline acetyltransferase (ChAT) in the taste cells and nerve fibers was absent. These data suggest that serotonin, CCK, VIP, substance P, and CGRP are involved in synaptic transmission or neuromodulation in the peripheral organs of taste. No evidence was found for cholinergic or adrenergic mechanisms on the basis of the absence of immunocytochemical staining for key enzymes involved in these two transmitter systems.
Distribution of the peptide Ala‐Pro‐Gly‐Trp‐NH2 (APGWamide) in the nervous system and periphery of the snail lymnaea stagnalis as revealed by immunocytochemistry and in situ hybridization
Authors: Croll Roger P. , Van Minnen Jan 
Published: May 2005

AbstractImmunocytochemistry and in situ hybridization were used to identify 200–250 central neurons that synthesize and contain the peptide APGWamide in the central nervous system of Lymnaea. The majority of these cells reside within the right anterior lobe of the cerebral ganglion and most appear to have projections to the ventral lobe of the ganglion. The neurites then branch to innervate the lobe and to send further projections into the penial nerve and to the Pelb cluster of the right pedal ganglion. The right ventral lobe also contains a cluster of about 30–40 somata, which apparently synthesize and contain APGWamide. Other populations of cells found in both the right and left anterior lobes project ipsilaterally to the pleural, parietal, and visceral ganglia. Prominent somata are also located in clusters in the visceral and right parietal ganglia. These cells project ipsilaterally into caudal neuropilar regions of the cerebral ganglia. Peripheral projections of central neurons form a dense plexus of varicose, APGWamide‐containing fibres in superficial layers of the penis and preputium. Other peripheral projections were noted in the prostate and vas deferens. No peripherally located cell bodies appeared to contain or synthesize the peptide. The results show that APGWamide is widely present in the central nervous system and male reproductive organs and suggest that it plays a major role in control of reproduction.
Morphological types of ganglion cells in the dog and wolf retina
Authors: Peichl Leo 
Published: May 2005

AbstractThe morphological types of ganglion cells in the dog and wolf retina were studied by intracellular staining with Lucifer Yellow. These retinae contain a range of ganglion cell types that closely correspond to those found in cat retina: alpha cells with large somata and large, relatively densely branched dendritic trees; beta cells with medium‐sized somata and small, densely branched dendritic trees; and a variety of other types with smaller somata and varying dendritic branching patterns and dendritic field sizes. The correspondence of canine and cat ganglion cell types strengthens the view that there is a common set of ganglion cell types in carnivores.Alpha and beta cell dendritic trees of dog and wolf are monostratified in either the inner or the outer part of the inner plexiform layer, suggesting an on/off dichotomy in the response to light. Dendritic field sizes of dog alpha and beta cells increase from the central area to peripheral retina: alpha cell fields from 160–200 μm to about 1,100 μm diameter, and beta cell fields from 25 μm to about 360 μm diameter. These sizes are quantitatively very similar to those found in cat retina. The close qualitative and quantitative morphological correspondence of cat and dog ganglion cells suggests that they are also functionally very similar. It is likely that dog alpha cells have brisk‐transient (Y), and dog beta cells brisk‐sustained (X) concentric receptive fields. From the smallest beta cell sizes it is concluded that the visual acuity of the dog may be as good as that of the Cat.
Distinctive pattern of organisation in the retinofugal pathway of a marsupial: I. Retina and optic nerve
Authors: Harman A. M. , Jeffery Glen 
Published: May 2005

AbstractThe nasotemporal division in the retina and the pattern of crossed and uncrossed axons in the optic nerve were determined in an Australian marsupial, a wallaby, Setonix brachyurus (the quokka), following unilateral horseradish peroxidase injections into primary visual centres. The gross morphology of the nerve was also examined. Ipsilaterally projecting ganglion cells were restricted to the temporal retina, whereas those that project contralaterally were located in all retinal regions. The morphological study of the nerve showed that fasciculation patterns, evident along much of the length of the nerve, became indistinct centrally and were replaced in the prechiasmatic region by dorsoventrally oriented fissures. In this prechiasmatic region, axons were oriented in two directions. Whereas the majority were aligned centroperipherally with the long axis of the nerve, a proportion were aligned dorsoventrally in the fissures. Labelling with HRP revealed that uncrossed axons were restricted to the lateral region of the optic nerve and possibly to discrete fascicles, whereas those destined to cross at the chiasm occupied all regions of the nerve but were less dense on the lateral side. This spatial distribution of crossed and uncrossed projections did not change along the length of the nerve. These results demonstrate that fibre organisation in the marsupial optic nerve is different than that found in eutherian mammals. © 1992 Wiley‐Liss, Inc.
Distinctive pattern of organisation in the retinofugal pathway of a marsupial: II. Optic chiasm
Authors: Jeffery Glen , Harman A. M. 
Published: May 2005

AbstractIn the mammalian optic chiasm retinal axons from each eye divide into two populations, those that decussate and those that remain uncrossed. In eutherian (placental) mammals, the separation of these pathways is not reflected in the structure of the chiasm. The two populations from each eye are mixed through each hemichiasm, segregating only at the midline, where the uncrossed projection turns back.In this study the optic chiasm of a marsupial, the wallaby, Setonix brachyurus (quokka) has been investigated with staining and neuronal tracing techniques. The chiasm of this mammal is quite different from that of eutherian mammals. In coronal section it can be morphologically subdivided into three regions, a central body in which fasciculated groups of axons from each eye interdigitate across the midline, and two distinct lateral regions, one on each side, which contain the uncrossed retinal projections. In the rostral chiasm the lateral regions are separated from the main body of the chiasm by vertically oriented fibre‐free regions. Caudally, the lateral regions increase in size and become less distinct as increasing numbers of contralaterally projecting axons that have crossed the midline project into them. However, the two populations remain predominantly segregated in this region. As the lateral regions develop, the central body of the chiasm becomes thinner and finally detaches at the midline to form the two optic tracts.The routes taken by retinal axons through the eutherian and marsupial chiasm appear to be fundamentally different. Therefore, the developmental factors that determine the laterality of retinal projections are likely to show significant differences in the two mammalian groups. © 1992 Wiley‐Liss, Inc.
Patterns of transmitter labelling and connectivity of the cat's nucleus of Darkschewitsch: A wheat germ agglutinin‐horseradish peroxidase and immunocytochemical study at light and electron microscopical levels
Authors: Onodera Satoru , Hicks T. Philip 
Published: May 2005

AbstractImmunocytochemical studies using antibodies raised against a number of probable synaptic transmitters of the mesodiencephalic area, and fibre‐tracing studies using wheat germ agglutinin‐horseradish peroxidase (WGA‐HRP), have been performed in adult cats. Glutamate and aspartate immunoreactivity produced a strong labelling of many cell bodies and terminals in the nucleus of Darkschewitsch (ND). γ‐Aminobutyrate (GABA) immunoreactivity in the ND appeared as a moderate label in some small neurones, and as a strong label in a few glial‐like cells, in addition to being present in high levels to produce strong labelling in many GABA‐immunopositive terminals that possessed pleomorphic vesicles. Some choline acetyltrans ferase‐positive terminals and dendrites and a few substance P‐positive fine fibres possessing varicosities also were observed in the ND.Following WGA‐HRP injection in the ND, dense terminal labelling was seen ipsilaterally in the rostral half of the medial accessory olive, suggesting that there may be a certain degree of mediolateral and dorsoventral topographic correspondance within the ND‐olive projection. In the same cases, many cell bodies containing HRP reaction product also were found (1) ipsilaterally in the motor cortex, anterior pretectal nucleus, and a restricted area of the caudal part of the substantia nigra pars reticulata; (2) contralaterally in the anterior and posterior interposed cerebellar nuclei as well as in a portion of the lateral cerebellar nucleu and (3) bilaterally in the zona incerta, the posterior pretectal nucleus, the pedunculopontine tegmental nuclei, the spinal trigeminal nucleus, the dorsal column nuclei, and the spinal cord. Details of the interrelationships and functional considerations amongst the ND, adjacent nuclei, and longitudinal zones of the cerebellum are discussed. © 1995 Wiley‐Liss, Inc.