bluuebunny/crossref_metadata_2025_split huggingface dataset:
Regeneration and soma size changes following axotomy of the trochlear nerve
Authors: Hazel Murphy E. , Brown Joyce , Iannuzzelli Pasquale G. , Baker Robert 
Published: January 2005

AbstractThe effects of CNS and PNS axotomy of the IVth nerve on cell death, soma size, axon size, and axon number were investigated. In adult cats, the IVth nerve was axotomised by using four surgical paradigms: (1) peripheral IVth nerve crush, (2) peripheral IVth nerve cut, (3) peripheral IVth nerve resection, and (4) a CNS IVth nerve cut in the velum. The extent of cell death resulting from each surgical paradigm was determined. Following axotomy distal to the decussation of the IVth nerves, cell death was least after nerve crush, intermediate after nerve cut, and maximal after resection of 5–7 mm of the nerve. Following axotomy at the decussationa CNS lesion‐most cells died but some successful regeneration was observed.Soma size measurements following a short‐term survival (3 days to 4 weeks) before the regenerating axons reached their target muscle revealed that somas of axotomised cells underwent hypotrophy within 1 week of axotomy and then gradually increased in size. They re‐attained normal size by 4 weeks postoperative when regenerating axons first reach their target. Following a long‐term survival (>2 months), somas were significantly hypertrophied, and the degree of hypertrophy was inversely related to the extent of cell survival up to a limit of 40% soma size increase.Counts and measurements of axons revealed that mean axon diameter of regenerated axons was much smaller than normal 3 months after axotomy, increased during the third to sixth postoperative months, but then showed no subsequent increase and remained below normal. In animals with cell death varying from 10% to 70%, the number of axons in the nerve was maintained constant at approximately 1,000. These data indicate that there is a mechanism for the production and maintenance of the appropriate number of regenerative axonal brabches following axotomy. In animals in which cell death exceeded 70%, the number of axons was controlled by a maximum ratio of 3 to 4 axon branches per surviving cell.The results suggest that axon number is strongly influenced by the target muscle and that hypertrophy of regenerated cells is related to the number of axonal sprouts each cell has to produce and suppot in order to re‐establish the preoperative number of axons in the regenerated trochlear nerve.
Organization of the histaminergic system in the brain of the turtle Chinemys reevesii
Authors: Inagaki Naoyuki , Panula Pertti , Yamatodani Atsushi , Wada Hiroshi 
Published: January 2005

AbstractTo accumulate phylogenetic information on the central histaminergic system, we investigated the histaminergic system in the brain of the Reeves turtle, Chinemys reevesii, using the indirect immunofluorescent method with antiserum against histamine. Histaminergic neuronal cell bodies were found exclusively in the posterior part of the ventral hypothalamus. Histaminergic varicose fibers innervated almost all parts of the turtle brain, but tended to be concentrated in several areas. Very dense innervation was observed in the medial part of the telencephalon, ventrolateral part of the hypothalamus, nucleus habenularis lateralis, and ventromedial part of the tegmentum. Medium density of innervation was seen in the olfactory bulb, nucleus medialis amygdalae, and tectum. Only a few fibers were detected in the lateral part of the telencephalon, dorsal part of the hypothalamus, thalamus, rhombencephalon, and spinal cord. The main ascending fibers were observed in the lateral part of the hypothalamus, sending dense fiber bundles to the cortices dorsomedialis and medialis and nucleus habenularis lateralis. Descending fibers appeared to run in the ventral tegmental area, passing through the dorsal and ventral parts of the midline of the brain stem to the spinal cord. These findings indicate that the general morphological features of the histaminergic system in the turtle brain are similar to those in the mammalian and frog brains.
Retinal vasculature of the fovea of the squirrel monkey, Saimiri sciureus: Three‐dimensional architecture, visual screening, and relationships to the neuronal layers
Authors: Max Snodderly D. , Weinhaus Richard S. 
Published: January 2005

AbstractThe retinal vasculature of the fovea of squirrel monkeys was studied in retinal whole mounts and in sections of the same retinas. At the center of the fovea there is an approximately circular avascular zone surrounded by a set of terminal capillaries in the inner nuclear layer. Within the foveal depression, four capillary planes that bear a precise relationship to the neuronal organization appear in a specific sequence with increasing eccentricity. The first plane to be established is the dominant, most voluminous one, located closest to the photoreceptors at the deep (sclerad) border of the inner nuclear layer. A second major plane appears next at the sclerad border of the ganglion cell layer.The two remaining, less voluminous planes occur at a slightly greater eccentricity. One of these, located at the shallow (vitread) border of the inner nuclear layer, often drains into the ganglion cell plane. The fourth plane is initially situated at the vitread border of the ganglion cell layer; with increasing eccentricity it moves into the nerve fiber layer. These capillaries are oriented like the nerve fibers with which they travel. Both the shallow inner nuclear and nerve fiber planes of capillaries show marked regional variations.The capillary planes are within or adjacent to regions of high cytochrome oxidase activity.The retinal vascular network is an unrecognized contributor to the optical filtering properties of the eye. In much of the central retina, a photon has a 40–50% chance of encountering one or more capillaries before it reaches a photoreceptor.
Motor neurons of grasshopper metathoracic ganglion occur in stereotypic anatomical groups
Authors: Siegler Melody V. S. , Pousman Cynthia A. 
Published: January 2005

AbstractAnatomical groups containing identified motor neurons of the main muscles of the legs and the wings are described in a segmental ganglion of the adult grasshopper. The groups occur reproducibly in ganglia of different individuals and are a simplifying and organizing feature of ganglionic morphology. The motor neurons within each group have cell bodies near each other in the cortex of the ganglion and primary neurites that enter the ganglionic core as a discrete bundle. The primary neurite bundles are distinctive in shape and position and have the same composition in every individual, despite variations in the positions of the cell bodies of the contributing motor neurons. The primary neurite bundle of a group is separate from those of other groups and separate from bundles of motor axons that exit or sensory axons that enter the ganglion. Each group of cell bodies in the cortex appears from light microscope examination to be held separately within a glial surround. Areas of glial cell cytoplasm may extend considerably beyond the boundaries of the neuronal cell bodies, to give shape and structural integrity to the cortex. Similarities between the morphology of the adult groups reported here and the descriptions by others of embryonic and larval nervous systems suggest to us that the motor neurons of each group are the progeny of a single neuroblast.
Horseradish peroxidase labeling of the central pathways in the medulla of the ampullary nerves in the chicken, Gallus gallus
Authors: Cox Robert G. , Peusner Kenna D. 
Published: January 2005

AbstractThe purpose of the present study was to place horseradish peroxidase on the distal processes of the three ampullary nerves in 6–8‐week‐old chickens so that we could identify the ganglion cells associated with each nerve and trace the specific central pathways taken by each nerve in the brainstem. We are especially interested in the pathways of the colossal vestibular fibers, which may play a role in a fast reflex pathway as suggested by their large caliber and electrotonic mode of transmission in the tangential vestibular nucleus.The cells of origin of each ampullary nerve occupy discrete portions of the vestibular ganglion. Those vestibular ganglion cells giving rise to the posterior ampullary nerve (PAN) occupy the posterior portion of Scarpa's ganglion; the ganglion cells producing the anterior (AAN) and lateral (LAN) ampullary nerves occupy the anterior ganglion, within the dorsal and ventral portions, respectively. Centrally the vestibular fibers occupy discrete portions of the tangential vestibular nucleus before bifurcating into ascending and descending tracts. The tangential nucleus receives afferents from the colossal fibers, which form spoon endings, and also from the fine vestibular fibers, which form small terminals. The ascending fibers of the posterior ampullary nerve are associated with the nucleus piriformis; the ascending fibers of the anterior and lateral ampullary nerves occupy discrete cell groups of the vestibulo‐cerebellar nucleus. All three ampullary nerves have descending branches that course through the retrotangential nucleus into the descending vestibular nucleus (DVN). Within the descending vestibular nucleus, the descending fibers of the posterior ampullary nerve run dorsally and centrally, whereas fibers of the anterior ampullary nerve course ventromedially, and the lateral ampullary nerve fibers take a ventrolateral course until all three fiber bundles converge in the posterior tip of the descending vestibular nucleus. The ascending and descending fibers of each ampullary nerve form collaterals that pass to the ventrolateral and dorsomedial parts of the medial vestibular nucleus. These collaterals are derived exclusively from the fine and medium diameter vestibular fibers. Some of these ascending fibers form a distinctive tract that courses posteriorly within medial regions of the dorsomedial part of the medial vestibular nucleus. The colossal vestibular fibers, which are found within all three ampullary nerves, conform to the ampullary pathways as described, excluding the innervation of the medial vestibular nucleus.
Distribution of neurotensin‐containing fibers in the frontal cortex of the macaque monkey
Authors: Satoh Keiji , Matsumura Hiroko 
Published: January 2005

AbstractThe distribution of neurotensin‐containing fibers was examined in the frontal cortex of the monkey Macaca fuscata using the immunoperoxidase histochemical technique. An extremely dense network of neurotensin‐containing fibers was observed in the medial prefrontal regions. The majority of cortical neurotensin fibers was observed in the anterior cingulate cortex (Walker's area 24) and adjacent medial prefrontal regions (areas 6 and 32). In area 24, the fiber density was similar to that in the nucleus accumbens. Immunoreactive fibers were particularly dense in two pyramidal layers (III, V). The medial prefrontal regions, areas 6 and 32, contained a moderate density of immunoreactive fibers. This regional distribution of neurotensin‐containing fibers was not observed in other cortical fiber systems that contained substance P, somatostatin, or tyrosine hydroxylase. No neurotensin‐containing cell bodies were observed in the frontal cortex.The present study demonstrates that the laminar and regional distributions of neurotensin‐containing fibers are unique when compared to those of substance P‐ or somatostatin‐containing fibers, and also distinct from that of catecholaminergic fibers. The distribution of telencephalic neurotensin fibers points to a relationship with limbic structures.
Cerebellar nucleo‐olivary projections in the rat: An anterograde tracing study with Phaseolus vulgaris‐leucoagglutinin (PHA‐L)
Authors: Ruigrok T. J. H. , Voogd J. 
Published: January 2005

AbstractIn order to evaluate the reciprocity of olivo‐cerebellar and cerebello‐olivary connections, a detailed description of the cerebellar nucleo‐olivary projection in the rat is presented using small, iontophoretic injections of the anterograde tracer Phaseolus vulgaris‐leucoagglutinin.Sparse projections were found to arise from the rostral part of the medial cerebellar nucleus toward the lateral part of the caudal medial accessory olive. Its medial parts receive a projection from the dorsolateral protuberance of the medial cerebellar nucleus. Caudal and lateral regions of the medial cerebellar nucleus project to the “beta” group and dorsomedial cell column.Heavy olivary projections to circumscribed parts of the inferior olive were found after injections in the remaining cerebellar nuclei. The medial part of the posterior interposed nucleus connects to caudolateral areas of the rostral half of the medial accessory olive, whereas lateral areas project to more rostromedial parts. The most ventromedial part of the lateral cerebellar nucleus projects to the ventrolateral outgrowth. Adjacent medial, ventral, and caudal regions connect to the ventral leaf of the principal olive. The cerebellar origin of the projection to its dorsal leaf is located in lateral, dorsal, and rostral parts of the lateral cerebellar nucleus. The dorsolateral hump projects to the dorsomedial group of the rat inferior olive. Rostromedial projections to the dorsal accessory olive originate from the lateral part of the anterior interposed nucleus, whereas its medial parts project to more lateral and caudal regions of this olivary subnucleus. The dorsal fold of the dorsal accessory olive does not receive a projection from the cerebellar nuclei but from the lateral vestibular nucleus. No cerebellar projections were found to the dorsal cap. Relatively strong ipsilateral projections, which were the mirror images of the contralateral projections, were observed in the dorsomedial group, rostral medial accessory olive, and ventral leaf of the principal olive.When both the inferior olive and the cerebellar nuclei are considered as folded but continuous sheets of grey matter, the complete nucleo‐olivary projection can be described as a simple transformation.
Localization and characterization of neuropeptide Y in the brain of Microcebus murinus (primate, lemurian)
Authors: Bons N. , Mestre N. , Petter A. , Danger J. M. , Pelletier G. , Vaudry H. 
Published: January 2005

AbstractThe distribution of neuropeptide Y (NPY) in the brain of the lemur Microcebus murinus was determined by immunocytochemistry with the aid of a highly specific antiserum against synthetic porcine NPY. When compared with previous immunohistochemical data obtained in primates and other mammalian species, the localization of NPY‐immunoreactive (IR) structures in the Microcebus murinus brain revealed particular features. (1) Numerous NPY‐IR perikarya and a dense network of IR nerve terminals were found in the supraoptic and suprachiasmatic nuclei, respectively. The occurrence of NPY‐IR perikarya in the supraoptic nucleus, also reported in the squirrel monkey, seems to be specific to primates. In the squirrel monkey, the suprachiasmatic nucleus exhibits only a moderate innervation, whereas in humans it appears totally devoid of NPY‐IR fibers. (2) IR perikarya and axon processes were observed in many upper brainstem areas, in particular in the interpeduncular, raphe pontine, dorsal tegmental, parabrachial, and dorsal raphe nuclei, in the locus coeruleus, the nucleus of the solitary tract, and the reticular formation; in this latter area, the occurrence of two categories of NPY‐IR neurons was demonstrated on the basis of their morphology and localization, suggesting that they may play distinct roles. (3) NPY‐IR nerve processes could be traced over a long distance. (4) For the first time, numerous NPY‐IR terminals were observed close to the lumen of the various cerebral ventricles. The immunoreactive NPY‐like peptide was characterized by combining high performance liquid chromatography (HPLC) analysis and radioimmunoassay quantification. The dilution curves obtained with synthetic porcine NPY and serial dilutions of occipital cortex, paraventricular and supraoptic hypothalamus, posterior hypothalamus, medulla oblongata, or preoptic area extracts were parallel. The highest amounts of NPY were measured in the hypothalamus and telencephalon. HPLC analysis resolved a single peak of NPY‐like immunoreactivity that exhibited the same retention time as synthetic porcine NPY. The distribution of NPY in the lemurian brain is discussed with respect to phylogeny and putative functions.
Projections from the lateral geniculate nucleus to the hypothalamus of the mongolian gerbil (Meriones unguiculatus): An anterograde and retrograde tracing study
Authors: Mikkelsen Jens D. 
Published: January 2005

AbstractThe lateral geniculate nucleus of the thalamus sends efferents to the hypothalamic suprachiasmatic nucleus, which is involved in generation and entrainment of several circadian rhythms. It seems reasonable to believe that the lateral geniculate conveys visual information about the length of the photoperiod to the circadian oscillator. In order to study in more detail the topographical relationship between the lateral geniculate and the suprachiasmatic nucleus, anterograde tracing with Phaseolus vulgaris leucoagglutinin (PHA‐L) and retrograde tracing with wheatgerm agglutinin coupled to horseradish peroxidase (WGA‐HRP) were performed in the gerbil.After iontophoretic injections of PHA‐L in the lateral geniculate, a large number of PHA‐L‐immunoreactive fibers and nerve terminals were observed in the ventrolateral part of the suprachiasmatic nucleus. Nerve fibers were also present in the ventromedial and dorsolateral portions, particularly in the caudal half of the nucleus. PHA‐L‐immunoreactive nerve fibers continued outside the borders of the suprachiasmatic nucleus to the adjacent anterior hypothalamic, the periventricular, and the subparaventricular areas. A moderate number of fibers entered the lateral hypothalamic area and the tuber cinerum via the optic tract and chiasm. Moreover, the paraventricular nucleus, the supraoptic nucleus, the medial preoptic area, the lateral preoptic area, and the supramammillary nucleus contained a few labeled fibers. In all parts of the hypothalamus receiving an input from the lateral geniculate, fine beaded immunoreactive fibers with varicosities and nerve terminals were observed, some of which were found in close apposition to hypothalamic neurons. Only after labeling of neurons in the intergeniculate leaflet of the lateral geniculate nucleus, fibers were found in the hypothalamus. This topographical organization of the geniculohypothalamic pathway was supported by retrograde tracing after injections of WGA‐HRP in the suprachiasmatic area. In these experiments, retrograde labeled neurons were observed in the intergeniculate leaflet and, in agreement with the anterograde studies, most of labeling was observed in the ipsilateral side. These results confirm that the suprachiasmatic nucleus receives a substantial input from the intergeniculate leaflet of the lateral geniculate. Moreover, the present data demonstrate that the suprachiasmatic nucleus is not the only nucleus that receives a direct visual input. Thus other hypothalamic areas might be influenced by a direct rhythmic neuronal input as well.
Morphology of the octopus cell area of the cochlear nucleus in young and aging C57BL/6J and CBA/J mice
Authors: Willott James F. , Bross Lori Seegers 
Published: January 2005

AbstractThe influence of aging and age‐related cochlear impairment on the ventral cochlear nucleus was evaluated by measuring morphological properties of the octopus cell area (OCA) in five age groups of inbred C57BL/6J and CBA/J mice (young adult to very old). The former strain demonstrates progressive cochlear sensorineural pathology and hearing loss during middle age; the latter has only modest sensorineural pathology late in life. Histological sections of the OCA were evaluated with serial sections and several stains for neurons, glia, and fibers, and Golgi impregnations were also used. Aging was associated with a decrease in volume of the OCA, a loss of neurons, slight decrease in neuron size, increased packing density of glial cells, and changes in dendrites ranging from minor to total loss of primary branches. The greatest changes occurred in extreme old age, beyond the median lifespan. Age‐related changes were not exacerbated by sensorineural pathology in aging C57BL/6J mice. Individual octopus cells varied greatly in the extent of age‐related abnormality.
Single fiber studies of ascending input to the cuneate nucleus of cats: I. Morphometry of primary afferent fibers
Authors: Weinberg Richard J. , Pierce Joseph P. , Rustioni Aldo 
Published: January 2005

AbstractThe morphology of afferent fibers ascending to the cuneate nucleus has been examined in this and the subsequent paper in order to quantify the pattern of arborization and bouton arrangement of selected classes of primary afferents and to compare these data with data from postsynaptic fibers ascending to the cuneate nucleus.Electrophysiologically identified G hair and la muscle afferent fibers in the cuneate fasciculus were intraaxonally injected with horseradish peroxidase. Cutaneous afferents terminated dorsal to proprioceptive afferents, especially at middle levels of the cuneate nucleus. The spacing of collaterals along G hair fibers was variable, but averaged 1.46 collaterals per mm; collateral density was higher at middle cuneate levels than in the rest of the nucleus. Collateral density of Ia fibers was lower than for G hair fibers and was lowest at caudal levels of the nucleus. Branches of G hair collaterals, though often initially diverging, usually converged to terminate in a single focus in the dorsal part of the nucleus. The probability of bifurcation of Ia collaterals decreased steadily at successive branch points. These collaterals branched less symmetrically than G hair collaterals, and terminated in the ventral cuneate with less dense arbors, stretched mediolaterally, but of comparable cross‐sectional area.Individual G hair collaterals gave rise to more boutons than Ia collaterals; in both cases they were mostly of the en passant type. Boutons were restricted to distal branches of G hair collaterals, whereas boutons of Ia collaterals were also located on proximal branches. Bouton size was similar for the two classes of collaterals.The data reported here, in combination with the published literature, suggest that the collaterals of roughly 300 G hair fibers overlap at any given point at middle levels of the cuneate nucleus. This high degree of anatomical convergence is not predicted by the functional segregation described with electrophysiological mapping, implying the presence of intrinsic nuclear mechanisms enhancing response specificity.