bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cholinergic and GABAergic afferents to the olfactory bulb in the rat with special emphasis on the projection neurons in the nucleus of the horizontal limb of the diagonal band
Authors: Záborszky L. , Carlsen J. , Brashear H. R. , Heimer L. 
Published: January 2005

AbstractWe have examined the location of cholinergic and GABAergic neurons that project to the rat main olfactory bulb by combining choline acetyltransferase (ChAT) and glutamic acid decarboxylase (GAD) immunohistochemistry with retrograde fluorescent tracing. Since many of the projection neurons are located in subcortical basal forebrain structures, where the delineation of individual regions is difficult, particular care was taken to localize projection neurons with respect to such landmarks as the ventral pallidum (identified on the basis of GAD immunoreactivity), the diagonal band, and medial forebrain bundle. In addition, sections with fluorescent tracers or immunofluorescence were counterstained for Nissl substance in order to correlate tracer or immunopositive neurons with the cytoarchitecture of the basal forebrain.The majority of the cholinergic bulbopetal neurons are located in the medial half of the nucleus of the horizontal limb of the diagonal band (HDB), whereas only a few are located in its lateral half. A substantial number of cholinergic bulbopetal cells are also found in the sublenticular substantia innominata. A small number of cholinergic bulbopetal neurons, finally, are located in the ventrolateral portion of the nucleus of the vertical limb of the diagonal band. At the level of the crossing of the anterior commissure, approximately 17% of the bulbopetal neurons in the HDB are ChAT‐positive. The noncholinergic bulbopetal cells are located mainly in the lateral half of the HDB.GAD‐containing bulbopetal neurons are primarily located in the caudal part of the HDB, especially in its lateral part. About 30% of the bulbopetal projection neurons in the HDB are GAD‐positive. A few GAD‐positive bulbopetal cells, furthermore, are located in the ventral pallidum, anterior amygdaloid area, deep olfactory cortex, nucleus of the lateral olfactory tract, lateral hypothalamic area, and tuberomamillary nucleus.The topography of bulbopetal neurons was compared to other projection neurons in the HDB. After multiple injections of fluorescent tracer in the neocortex, retrogradely labeled neurons were concentrated in the most medial part of the HDB, while neurons projecting to the olfactory and entorhinal cortices were located in the ventral part of the HDB. These results show that the cells of the HDB can be divided into subpopulations based upon projection target as well as transmitter content. Furthermore, these subpopulations correspond, at least to a considerable extent, to areas that can be defined on cyto‐ and fibroarchitectural grounds.
Age‐Dependent occurrence of an ascending axon on the omega neuron of the cricket, Teleogryllus oceanicus
Authors: Atkins Gordon , Pollack Gerald S. 
Published: January 2005

AbstractThe omega neurons (ON1s) are a mirror‐symmetrical pair of identified prothoracic auditory interneurons of crickets which have been previously described as intraganglionic. Using intracellular techniques we stained ON1s of female Teleogryllus oceanicus and found that many ON1s have axons which project anteriorly out of the prothoracic ganglion. The ascending axon arises contralateral to the soma at the most anteriolateral bend of the bowshaped process of an otherwise “archetypical” ON1 and travels up the neck connective in a ventral position just inside the connective tissue sheath. The occurrence of the ascending axon is age‐dependent. Seventy‐five percent of ON1s stained in late nymphal stages and in young adults had an ascending axon while only 30% of ONis in older adults had an ascending axon. Evidence is presented to show that ON1s having ascending axons are developmental variants of the “archetypical” ON1 and do not represent a separate neuron type. The two morphological types of ON1s are not distinguishable on the basis of their responses to sound stimuli having carrier frequencies of 3.5‐60 kHz. Although we know that the ascending axon conducts action potentials, its target and terminal morphology are not yet known.
Oral and facial representation in the trigeminal principal and rostral spinal nuclei of the cat
Authors: Shigenaga Yoshio , Okamoto T. , Nishimori T. , Suemune S. , Nasution I. D. , Chen I. C. , Tsuru K. , Yoshida A. , Tabuchi K. , Hosoi M. , Tsuru H. 
Published: January 2005

AbstractTransganglionic transport of horseradish peroxidase (HRP) was used to study the patterns of termination of somatic afferent fibers innervating oral and facial structures within the principal nucleus (Vp), nucleus oralis (Vo), and nucleus interpolaris (Vi). The primary trigeminal afferent fibers that innervate the oral cavity supplied by the pterygopalatine, superior alveolar, lingual, buccal, and inferior alveolar branches, as well as the facial skin sunnlied by the frontal, corneal, zygomatic, infraorbital, auriculotemporal, mylohyoid, and mental branches, were traced in this experiment. The results show that trigeminal afferent nerves that innervate the oral cavity project mainly to the principal nucleus, the rostrodorsomedial part (Vo.r) and dorsomedial division (Vo.dm) of pars oralis, and the dorsomedial region of pars interpolaris, while an extensive overlap of projections is found in the Vo.r, Vo.dm, and rostral Vi. The central processes of fibers innervating the anterior face (i.e., mental, infraorbital, and frontal nerves) terminate in the ventral division of principalis (Vpv), caudal region pars oralis (Vo.c), and ventrolateral Vi, with the largest numbers of terminals being found in the Vpv and Vi. In contrast, the central projection patterns of the corneal, zygomatic, mylohyoid, and auriculotemporal afferents are different from those of other afferent nerves examined, and present a discrete projection to the trigeminal sensory nuclear complex (TSNC). The corneal, mylohyoid, and auriculotemporal afferents mainly project to the restricted regions of principalis and caudal Vi, while zygomatic afferent nerve fibers project to the caudal third of pars interpolaris. The typical somatotopic organization with the face of the mouth open inverted is represented in the rostrocaudal midlevels of the Vpv and caudal pars interpolaris. The Vpd receives topographical projection from primary afferent nerves that innervate the oral structure only, while this projection was organized in a complicated manner. The relationship between the functional segregation and the cytoarchitectonic differentiation of the TSNC is discussed, particularly with respect to this somatotopic organization, combined with the characteristics of projecting cells in the TSNC.
A Golgi study of the neuronal population of the marginal zone (lamina I) of the rat spinal cord
Authors: Lima Deolinda , Coimbra Antonio 
Published: January 2005

AbstractOn the basis of dendroarchitecture and cell body shape, complemented with morphometry of dendritic ramification, four major neuronal types were distinguished in lamina I of the spinal cord of the rat. (I) Fusiform spiny cells (39% of impregnated neurons) have longitudinal spindle‐shaped perikarya with bipolar, less frequently unipolar, dendritic trees rich in pedicled spines and a thin, beaded longitudinal axon; such neurons occur mainly in the lateral marginal zone. In type IA cells (33% of the total), the dendritic domain occupies a narrow longitudinal area, while in type lb cells (6%) the polar dendritic trees partly arborize ventrally. Fusiform neurons are considered intrinsic cells connected with the longitudinal afferent plexus in lateral lamina I, and in type IB cells also receiving primary input in the substantia gelatinosa. (II) Multipolar cells (23%) have a dense dendritic arbor originating from numerous primary trunks and they predominate in the medial marginal zone. The dendritic arbor is moderately extended dorsoventrally in type IIA cells and reaches lamina III in the larger type JIB cells. The former possess a variety of spines, axonlike processes and sometimes an unmyelinated axon, and are presumably interneuron's, while type IIB cells show a thick tapering axon that is probably myelinated. (III) Flattened aspiny neurons (13%) with a polygonal body flattened in the horizontal plane, and a horizontal dendritic arbor confined to lamina I; these cells predominate in middle lamina I. (IV) Pyramidal neurons (25%) have longitudinally elongated perikarya that bulge into the white matter. The arbor has a large longitudinal and lateromedial spread and includes branches which ramify in the white matter. Types III and IV show the classical lateromedially elongated orientation of the marginal cells of the old literature; they show thick tapering axons and probably make up the bulk of the projection neurons of rat lamina I.
Mauthner neurons survive metamorphosis in anurans: A comparative HRP study on the cytoarchitecture of Mauthner neurons in amphibians
Authors: Will Udo 
Published: January 2005

AbstractGiant medullary neurons were revealed in adult Xenopus laevis and Rana esculenta following HRP injections to the spinal cord. These neurons were identified as Mauthner neurons because (1) they have the same position and orientation as the larval Mauthner neurons, i.e., they lie at the level of the VIIIth nerve root. (2) they have two large dendritic trees that for each species are similar to those of the larval Mauthner neurons, (3) they are clearly distinguishable from other large reticular neurons, (4) they have close connections with the VIIIth nerve afferents, (5) they have a decussating descending axon, the largest of the adult brainstem, and (6) they have a reduced axon cap, i.e., a dense neuropil without cap dendrites.Mauthner neurons were also identified in adult Xenopus muelleri, Hymenochirus curtipes, Hyla cinerea, Rhacophorus leucomystax, and Kalula pulchra.No Mauthner neuron was identified in larval or adult Bombina bombina or Bufo bufo or in adult Bufo terrestris, Bombina orientalis, or Scaphiopus holbrookii.Cytoarchitecture and the elaborate dendritic trees were also revealed in urodeles. Mauthner neurons of terrestrial forms (Ambystoma tigrinum, Paramesotriton chinensis) exhibit a less‐extensive branching of the “lateral line” dendrite but otherwise show no signs of involution or regression compared to aquatic forms (Siredon mexicanum, Cynops pyrrhogaster).No Mauthner neuron was identified in larval or adult Ichthyophis kohtaoensis.Besides the topographical relations between Mauthner neurons and afferent fibers from the lateral line and the VIIIth nerve we could demonstrate a projection of trigeminal and mesencephalic neurons onto the soma of the amphibian Mauthner neuron.
Choline acetyltransferase immunoreactivity suggests that ganglion cells in the goldfish retina are not cholinergic
Authors: Tumosa N. , Stell W. K. 
Published: January 2005

AbstractPublished evidence that ganglion cells in the retinae of nonmammalian species are cholinergic is strong but indirect. In this paper we report results of attempts to demonstrate choline acetyltransferase immunoreactivity in ganglion cells of goldfish retina using two different antisera against choline acetyltransferase (ChAT), the acetylcholine‐synthesizing enzyme.We obtained ChAT‐immunoreactive staining of amacrine and displaced amacrine cells in the retina and type XIV cells in the tectum, but we obtained no direct immunocytochemical evidence that ganglion cells in the goldfish retina are cholinergic. Thus, ganglion cells identified by retrograde transport of propidium iodide were never ChAT‐immunoreactive. Intraocular injections of colchicine did not result in the appearance of a population of ChAT‐immunoreactive neurons in the ganglion cell layer. ChAT‐immunoreactive axons were not observed in intact, ligated, or transected optic nerves. And finally, the ChAT immunoreactivity of cells and fibers in the optic tectum was unaffected by deafferentation.These experiments provide no positive evidence that any ganglion cells in goldfish retina contain the acetylcholine‐synthesizing enzyme, ChAT. While it is possible that our method is too insensitive to detect the enzyme in ganglion cell somata or too specific to recognize the form of ChAT present in these cells, the fact that we can stain putatively cholinergic retinal amacrine cells and tectal neurons makes these alternative explanations improbable. We conclude that it is unlikely that any of the ganglion cells in the retina are cholinergic and that alternative explanations should be sought for previously published results that suggest that they are.
Distribution of immunoreactive somatostatin (ISRIF) in the nervous system of the squid, Loligo pealei
Authors: Feldman Susan C. 
Published: January 2005

AbstractSomatostatin (SRIF) is a neuropeptide with a ‐widespread distribution in the mammalian CNS. In the present study we have examined the distribution of immunoreactive‐like SRIF (ISRIF)‐containing elements in the nervous system of the cephalopod mollusk Loligo pealei or the Woods Hole squid. ISRIF was localized by light immunocytochemistry in sections of the squid—optic lobe, circumesophageal ganglia—and in stellate ganglion. In the optic lobe, ISRIF neurons were found in the internal granule cell layer and medulla and immunoreactive fibers were seen throughout the lobe and in the optic tract but were absent from the optic nerve, i.e., the projection between the retina and optic lobe. In the supraesophageal complex, ISRIF neurons were found in all lobes, but primarily in the vertical, subvertical, and frontal. In the subesophageal ganglion, ISRIF neurons were seen mainly following unilateral pallial nerve lesions; these neurons were primarily small‐to‐medium sized. ISRIF fibers were seen in many of the nerves exiting from the brain and in nerves extending between the sub‐ and supra‐esophageal ganglia. In the stellate ganglion, ISRIF was present in many neurons as well as in a plexus of fibers within the ganglion; the peptide was absent from the second‐order fibers and the giant axon.The data suggest that a molecule immunologically similar to vertebrate SRIF may be a major transmitter/modulator in this invertebrate. These results provide a foundation for further studies to evaluate the role of this molecule.
Plasticity in the olfactory cortex: Age‐dependent effects of deafferentation
Authors: Friedman Beth , Price J. L. 
Published: January 2005

AbstractIn order to assess the role of input‐target interactions in the development of olfactory ccrtex, the primary afferent fibers from the olfactory bulb to the superficial part of layer I of the cortex (layer Ia) were removed in developing and mature rats. After survival periods that vary from a few days to 2–6 months, changes were assessed in (1) the radial thickness of layer I, (2) the laminar distribution of intracortical associational fibers, which normally terminate in a deep part of layer I (layer Ib), and (3) the distribution of glia in layer I. The findings indicate that the lamination of fibers within layer I is not intrinsically prespecified, but gradually becomes “set” during the first month after birth. If the fibers from the olfactory bulb are removed, the dendrites of cortical cells are capable of accepting inputs from other fiber systems, depending on the maturational state of the dendrites and the ingrowing axons. Development of the abnormal inputs is associated with relatively normal dendritic growth, whereas lack of adequate input results in dendritic atrophy.Thus, after neonatal bulb ablation, the intracortical fibers occupy both superficial and deep parts of layer I, and a normal synaptic density is established throughout the layer. Layer I also develops to nearly its normal adult thickness, although the high density of glia that normally characterizes layer Ia is not apparent. With bulb ablation at progressively older ages (from postnatal day (P‐) 3 to 21), the cortical associational fibers show progressively less extension into the denervated layer Ia. Layer I continues to grow, but rut to the same extent as after P‐1 ablations. In these experiments the glia distribution resembles the pattern present at the time of denervation. After adult olfactory bulb albation, the long intracortical fibers extend very little into layer Ia, which undergoes pronounced shrinkage and becomes filled with a high concentration of glia. However, partial reinnervation of layer Ia is accomplished by the proliferation of a normally sparse native fiber system, which has been identified only with the Timm method.These results are interpreted as evidence that the normal development of lamination of afferent fibers to the olfactory cortex depends on axodendritic interaction during development.
Age‐dependent cell death in the olfactory cortex: Lack of transneuronal degeneration in neonates
Authors: Friedman B. , Price Joseph L. 
Published: January 2005

AbstractAdult olfactory cortical neurons in layer IIa undergo fulminant transneuronal degeneration after removal of afferent olfactory bulb fibers (Price, '76, Neurosci Abst. 2:161; Heimer and Kalil, '78, J. Comp. Neurol 178:559‐609). This provides an unusual example of dependence of a mature population of neurons on axonal input. In order to investigate whether similar transneuronal degeneration occurs in immature animals, a series of rats were subjected to unilateral olfactory bulb removal at various ages during the first 3 postnatal weeks. The brains were examined for degeneration after short survivals by use of the de Olmos cupric silver method, which selectively stains degenerating neurons. In addition, animals with long survivals were examined with the HRP retrograde tracing method, in order to determine if cells that survive the acute effects of deafferentation develop normal patterns of connections.Young neurons are more resistant to the effects of olfactory bulb removal than more mature neurons. There was little degeneration of cortical neurons after bulb ablation during the first 2 postnatal, weeks. Although layer IIa does not become distinct from layer IIb in, these experimental animals, cells that have connections normally characteristic of the cells of layer IIa, and are situated at the superficial edge of layer II, were identified with the HRP method. The severity of transneuronal degeneration increases and becomes adultlike between the second and third postnatal weeks. This increase in transneuronal degeneration is temporally associated with a progressive reduction in axonal sprouting following deafferentation during the first 3 postnatal weeks, as described in the companion paper (Friedman and Price, '86). Thus, axon sprouting may “protect” the immature IIa neurons from the effects of removal of the fibers from the olfactory bulb.A period of normal cell death has also been identified in olfactory cortex by the use of the de Olmos cupric silver method. This cellular degeneration is much less severe and has a different time course and laminar distribution than the transneuronal degeneration produced by olfactory bulb ablation in adults. Although normal cell death appears to be potentiated by removal of the olfactory bulb on postnatal day 1, it is clearly a different process from the transneuronal reaction.
Identification of distinct topographical distributions of lumbar sympathetic and sensory neurons projecting to end organs with different functions in the cat
Authors: Jänig W. , McLachlan Elspeth M. 
Published: January 2005

AbstractA comparison has been made between the lumbar sensory and sympathetic pre‐ and postganglionic neurons that project in the lumbar splanchnic nerves and those that project in the caudal lumbar sympathetic trunk of the cat. The neuron cell bodies have been labeled retrogradely with horseradish peroxidase applied to the central end of their cut axons near the inferior mesenteric ganglion on one side, and the results have been compared with those obtained after labeling the contralateral lumbar sympathetic trunk of the same animal (Jänig and McLachlan, '86). The numbers, segmental distribution, location, and size of the labeled somata have been determined quantitatively. The data for individual animals confirm in every way those previously reported for separate experiments in different groups of animals. In addition, similar experiments were performed in which the neurons projecting in the white rami of either L4 or L5 were labeled. This procedure labeled populations of neurons that overlapped both splanchnic and paravertebral populations. Consideration of the spatial distributions and numbers of sensory and preganglionic neurons with destinations in somatic and visceral domains has enabled us to describe the different topography of these neuron populations with respect to function.
Single thalamic neurons project to both lateral suprasylvian visual cortex and area 17: A retrograde fluorescent double‐labeling study
Authors: Tong Lillian , Spear Peter D. 
Published: January 2005

AbstractArea 17 and the posteromedial lateral suprasylvian (PMLS) visual cortex receive inputs from three thalamic nuclei in common: the lateral division of the lateral posterior nucleus (LPI), the C‐laminae of the lateral geniculate nucleus (LGNd), and the medial interlaminar nucleus (MIN). The present study determined whether these projections originate from the same cells via bifurcating axons or from separate populations of cells. Double‐label retrograde transport techniques were used to label cells projecting to area 17 with one fluorescent dye and to label cells projecting to PMLS cortex with a different dye. The two dyes used were fast blue and Evans blue. Following injections into the two cortical areas, some cells were double labeled and some were single labeled in all three thalamic nuclei studied. However, the relative number of double‐ and single‐labeled cells, as well as the relative number of cells single‐labeled following injections into each cortical area, differed among the three thalamic nuclei. In both MIN and the C‐laminae of the LGNd, the number of double‐labeled cells was small. Similarly, the number of cells single labeled with the dye placed in PMLS cortex was small in these two nuclei. In contrast, a relatively large number of cells were single labeled with the dye placed in area 17, especially in the C‐laminae of the LGNd. These results suggest that in both MIN and the C‐laminae of the LGNd, few cells project to both area 17 and the PMLS cortex, few cells project only to PMLS cortex, and a relatively greater number of cells project only to area 17. In LPl, many cells were labeled after the cortical injections. In fact, when the areas of densest labeling for both dyes overlapped, almost every labeled cell in LPl was double labeled. This indicates that almost all LPl cells that project to one cortical area also project to the other via a bifurcating axon.