bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of chorda tympani nerve taste responses in the hamster
Authors: Hill David L. 
Published: January 2005

AbstractTo determine whether changes in salt and sugar responses occur during development in the hamster, multifiber responses were recorded from the chorda tympani nerve while stimulating the anterior tongue of preweanling, early postweanling, and adult hamsters. Gustatory stimuli included 0.1 and 0.5 M solutions of NH4Cl, NaCl, LiCl, and KCl, and concentration series (0.01–1.0 M) of glucose, fructose, sucrose, maltose, lactose, and (0.0005–0.01 M) saccharin.Dramatic alterations in hamster peripheral gustatory sensitivities occurred with age, with the direction and magnitude of change dependent on the specific stimulus. Response magnitudes to 0.1 M solutions of NaCl and LiCl decreased with age compared to the NH4Cl response, whereas responses to all other salt stimuli remained constant during development. Responses to all sugars and saccharin compared to the NH4Cl response increased during development across a large concentration range; however, the age at which mature responses were achieved depended on the specific “sweet” stimulus.Whereas these findings demonstrate that the hamster peripheral gustatory system is dynamic during postnatal development, the hamster has a unique developmental pattern of salt taste development compared to other species. Specifically, the effectiveness of NaCl and LiCl decrease during development compared to NH4Cl in the hamster, but increase dramatically in the rat and sheep. Thus, the developmental patterns are opposite in direction for the hamster compared to the rat and sheep and may relate to the environmental pressures imposed upon each species.
Comparative topography of projections from the mesodiencephalic junction to the inferior olive, vestibular nuclei, and upper cervical cord in the cat
Authors: Spence Sandra J. , Saint‐Cyr Jean A. 
Published: January 2005

AbstractDistributions of neurons located in the central rostral mesencephalon and caudal diencephalon that project to the upper cervical spinal cord, vestibular nuclei, or inferior olive were studied in the cat by using retrograde axonal transport of wheat germ agglutinin conjugated to horseradish peroxidase (WGA‐HRP). Afferent sources to all of these targets were observed in the interstitial nucleus of Cajal (INC), the region surrounding the fasciculus retroflexus (PF), and the nucleus of the fields of Forel (NFF). Three‐dimensional reconstruction revealed differences in densities of cells projecting from these common areas. Spinal projecting cells were present in slightly greater numbers in the caudal two‐thirds of the INC, whereas those projecting to the vestibular complex were more numerous in the rostral two‐thirds of this nucleus. A relatively smaller number of olivary projecting cells were dispersed throughout the INC. Olivary afferent sources outnumber those with spinally directed or vestibularly directed axons in the PF region. In the fields of Forel, cells projecting to the vestibular nuclei or inferior olive were concentrated medially, whereas cells projecting to the spinal cord appeared both medially and laterally. Each type of afferent source was also seen in the nucleus of the posterior commissure and the posterior ventral lateral hypothalamic area. Unique sources of afferents to the inferior olive were observed in the parvicellular red nucleus (ipsilateral to the injections) and the anterior and posterior pretectal nuclei. A large number of labeled neurons was seen in the nucleus of Darkschewitsch after injections of tracer into the inferior olive, but this projection did not appear to be unique, as small numbers of labeled cells were also seen after injections into the cervical spinal cord. The Edinger‐Westphal nucleus and the adjacent somatic oculomotor nucleus contained cells which projected separately to the spinal cord or the vestibular complex, and the superior colliculus contained cells which projected separately to the contralateral spinal cord or the contralateral inferior olive. In this study, it was also noted that neurons in the medial terminal nucleus of the accessory optic tract projected to the ipsilateral inferior olive or to the contralateral vestibular complex. These differences in locations and densities of cells projecting to the cervical spinal cord, vestibular complex, and inferior olive may underlie functional specializations in these areas in relation to vertical eye and head movement control and to neural systems controlling postural adjustments accompanying limb movements.
Auditory brainstem of the ferret: Sources of projections to the inferior colliculus
Authors: Moore David R. 
Published: January 2005

AbstractThe organization of the auditory brainstem in adult, darkly pigmented ferrets was studied by using the retrograde transport of the lectin wheat germ agglutinin–horseradish peroxidase injected into one inferior colliculus. Retrogradely labelled neurons were found bilaterally in every nucleus of the auditory brainstem. The greatest number of labelled neurons was found in the cochlear nuclei contralateral to the injection site, the ipsilateral medial superior olivary nucleus, both lateral superior olivary nuclei, the ipsilateral ventral nucleus of the lateral lemniscus, both dorsal nuclei of the lateral lemniscus, and the contralateral inferior colliculus. Quantitative assessment of the projections from the cochlear nuclei showed that the number of contralaterally projecting neurons exceeded the number of ipsilaterally projecting neurons by about 50 to one. This ratio remained relatively stable over a wide range of volumes of injected lectin, whereas the absolute number of labelled neurons on each side varied by at least twofold for a constant volume of lectin. These results provide basic data on the ferret auditory system and demonstrate quantitatively some properties of the projections between the cochlear nucleus and the inferior colliculus.
Unilateral odor deprivation: Early postnatal changes in olfactory bulb cell density and number
Authors: Frazier Lauren L. , Brunjes Peter C. 
Published: January 2005

AbstractSurgical closure of an external naris of the rat from postnatal day 1 to day 30 results in a 25% decrease in the size of the ipsilateral olfactory bulb. Decreases in size must result from changes in either the number of neurons and/or glia, or their size or both. The present study was designed to quantify cell density (Nv) and number at various early postnatal ages in order to examine both normal patterns of maturation and sequences of change resulting from deprivation.Data from control subjects indicated that numbers of mitral cells remained constant while numbers of external tufted cells increased. Both relay cell populations exhibited increases in nuclear size suggestive of substantial postnatal differentiation. All interneuronal and glial populations increased in number, although differences in maturational patterns were observed between cell species. For example, light and dark subpopulations of granule cells differed in the timing of peak cellular density, and an inside‐to‐outside gradient of maturation was found for dark granule cells.Growth curves were generally similar in occluded and control pups until approximately day 20, when deprivation resulted in decreased number and nuclear area of external tufted cells and density and number of granule cells and their associated glia. Light granule cells were affected earlier than dark cells, perhaps because of their earlier arrival in the granule cell layer. The affected cell groups represent the last relay and interneuronal populations to be generated, perhaps explaining their particular susceptibility to the effects of experience. Most of the changes emerged late, thus suggesting that they represent the culmination of a series of experience‐induced changes within the maturing bulb. The observed effects may result from either altered cellular proliferation or death patterns (or both), alternatives now under investigation.
Atlas of serotonin‐containing neurons in the optic lobes and brain of the crayfish, Cherax destructor
Authors: Sandeman D. C. , Sandeman R. E. , Aitken A. R. 
Published: January 2005

AbstractAn atlas of neurons in the brain of the crayfish Cherax destructor that are immunoreactive to antibodies raised against serotonin has been compiled from whole mount preparations. Neuronal networks of serotonin‐containing cells are identified in the optic lobes and protocerebrum, in the deutocerebrum, and in the tritocerebrum. The consistency of the whole‐mount technique allows 50 out of a total of about 100 immunoreactive cells to be individually identified according to their neuronal architecture or the location of their cell somata or axons. Apart from six neurons with axons in the oesophageal connectives, all the immunoreactive cells are intrinsic to the optic lobes and brain.
Anatomy of macaque fovea and spatial densities of neurons in foveal representation
Authors: Schein Stanley J. 
Published: January 2005

AbstractFine visual sampling in the macaque depends on the high density of cone outer and inner segments in the fovea. Cone pedicles, at the opposite, presynaptic end of the cone, are absent from the center of the fovea. Both ends of the cones, inner segments and pedicles, are closely packed within their respective monolayers, but the spatial density of foveal pedicles is lower because foveal pedicles are wider than inner segments. Because there is one pedicle for every inner segment, and because pedicles are wider than inner segments, increase in eccentricity finds increasing lateral displacement of the cone's pedicle from its inner segment. Further increase of eccentricity finds inner segment density falling below pedicle density, and so this lateral displacement declines. By 2–3 mm from the center, inner segments catch up with pedicles. Additional lateral displacements, of bipolar cells from pedicles and ganglion from bipolar cells, are largest for central‐most elements and fall steeply with eccentricity.By taking into account all of these lateral displacements, the eccentricity of the cone inner segment(s) associated with a ganglion cell was determined, as was the area of inner segments represented by a unit area in the ganglion cell layer. Then raw ganglion cell densities were transformed to densities comparable to densities of inner segments and of cells in dorsal lateral geniculate nucleus. On average there appears to be close to 2 ganglion cells for each cone in the central fovea out to about 2.5°. Thus, the density of foveal ganglion cells is sufficient to allow each red and each green cone to connect to 2 midget ganglion cells, and each blue cone to connect to 1 ganglion cell. Furthermore, there appears to be a single dorsal lateral geniculate cell for each ganglion cell.
Fibers from the basolateral nucleus of the amygdala selectively innervate striosomes in the caudate nucleus of the cat
Authors: Ragsdale Clifton W. , Graybiel Ann M. 
Published: January 2005

AbstractThe compartmental organization of the amygdalostriatal projection was studied in the cat by comparing staining patterns seen by cholinesterase enzyme histochemistry with the distribution of fibers labelled with a horseradish peroxidase–wheat germ agglutinin conjugate or by incorporation of 35S‐methionine or 3H‐leucine. Fibers from the basolateral nucleus of the amygdala were found to innervate selectively acetylcholinesterase‐poor striosomes demonstrated in the caudate nucleus and butyrylcholinesterase‐rich zones observed in the anterodorsal nucleus accumbens. In no case were the amygdalar fibers fully restricted to striosomes, but the nature and degree of labelling of the striatal matrix, as well as the range of the labelled fibers in dorsal striatum, varied with the positions of the injection sites.
Pathway specificity of reticulospinal and vestibulospinal projections in the 11‐day chicken embryo
Authors: Glover Joel C. , Petursdottir Gudrun 
Published: January 2005

AbstractThe organization of the axonal pathways of reticulospinal and vestibulospinal projections in the 11‐day chicken embryo was ascertained through retrograde tracing experiments. An in vitro reparation of the brainstem and cervical spinal cord facilitated precisely localized tracer applications. Single‐ and double‐labelling experiments involving high cervical injections of tracers in combination with selective lesions defined the specific pathways by which different brainstem neurons project to the spinal cord. Coherent, and in many cases distinct, groups of reticulospinal and vestibulospinal neurons could thus be identified on the basis of their position and projection pathway. The organization of these groups and their projections in the 11‐day chicken embryo is similar to that in avian and other vertebrate adults and therefore serves as a reference point for studies of path finding by bulbospinal axons during early development.
Serotoninergic innervation of the cat cerebral cortex
Authors: Mulligan Kathleen A. , Törk Istvan 
Published: January 2005

AbstractSerotoninergic axons in the cat cerebral cortex were demonstrated immunohistochemically with a monoclonal antibody to serotonin (5‐HT). Three types of 5‐HT axons are distinguished at the light microscopic level by differences in their morphology. Small varicose axons are fine (less than 0.5 μm) and bear fusiform varicosities that are generally less than 1 μm in diameter. These axons extend throughout the width of the cortex and branch frequently, giving rise to widely spreading collaterals. Nonvaricose axons are smooth, show a relatively large and constant caliber (about 1 μm), travel in straight, horizontal trajectories, and branch infrequently. Large varicose axons are distinguished by large round or oval varicosities (1 μm or more in diameter) borne on fine‐caliber fibers. These axons often form basketlike arbors around the somata of single neurons. In the simplest basketlike arbors, several large, round varicosities from a small number of axons contact the soma. In complex baskets intertwining collaterals contact the soma and apparently climb along and outline the cell's major dendrites. The patterns revealed by the climbing axons suggest that a variety of nonpyramidal cell types selectively receive dense 5‐HT innervation.Serial reconstructions of the 5‐HT axons within the cortex show that the large varicose axons arise as infrequent collaterals from the nonvaricose axons. A single nonvaricose parent axon gives rise to several large varicose axon collaterals that may contribute to different basketlike arbors. Conversely, a single basketlike arbor may be formed by large varicose axon collaterals from more than one nonvaricose parent axon. The small varicose axons do not appear to be related within the cortex to either the nonvaricose or large varicose axon types.The results support the hypothesis that the 5‐HT projection to the cortex is organized into two subsystems, one of which may exert widespread influence in the cortex via highly divergent branches, while the other, with a more restricted distribution, acts on specific classes of cortical neurons.
Catecholamine neurons in the brainstem of the reptile Caiman crocodilus
Authors: Brauth Steven E. 
Published: January 2005

AbstractImmunohistochemical methods were used to map the distribution of neurons exhibiting tyrosine hydroxylase‐like immunoreactivity (TH) in the brainstem of the reptile Caiman crocodilus.The results reveal that many catecholamine systems previously described in mammalian and avian species are present in the brainstem of the caiman. Within the medulla, many immunoreactive neurons surround the central canal. This neuronal field extends rostrally to the level of the dorsal motor nucleus of the vagus. Many TH neurons overlap the region of the solitary nucleus, and an extensive system of fibers derived from these neurons extends ventrally and laterally into the region immediately bordering the descending nucleus of the trigeminal nerve Some TH neurons are also present in the ventrolateral tegmentum of the medulla at this level.A large number of TH cells are present in the pons and midbrain. These include the locus coeruleus, nucleus subcoeruleus ventralis, nucleus subcoeruleus dorsalis, substantia nigra (Brauth et al., '83), and area ventralis of Tsai. The subcoeruleus nuclei are considerably larger in the caiman than in other reptilian species including turtles and lizards and closely resemble the subcoeruleus nuclei of birds in terms of position and anterior‐posterior extent. Within the diencephalon, numerous small, intensely staining, TH‐immunoreactive and CSF‐contacting neurons were observed within the preoptic recess and in close proximity to the ventricular wall at rostral hypothalamic and preoptic levels. Many intensely stained, immunoreactive cell bodies were observed in the medial hypothalamus similar in position to the A13 cell group of mammals. In the subthalamus, TH neurons completely surround the ventral peduncle of the forebrain bundle (which contains fibers of the ansa lenticularis) and extend into the ventromedial and ventrolateral thalamic areas. A rich plexus of TH‐positive axons and terminals invests the external layer of the median eminence.
Histochemical localization of cytochrome oxidase in the retina and optic tectum of normal goldfish: A combined cytochrome oxidase‐horseradish peroxidase study
Authors: Kageyama Glenn H. , Meyer Ronald L. 
Published: January 2005

AbstractCytochrome oxidase (C.O.) was histochemically localized in the normal retina and optic tectum of goldfish in order to examine the laminar and cellular oxidative metabolic organization of these structures. In the optic tectum, C.O. exhibited a distinct laminar, regional, and cellular distribution. The laminae with highest C.O. levels were those that receive optic input, suggesting a dominant role for visual activity in tectal function. This was demonstrated by colocalizing C.O. and HRP‐filled optic fibers in the same section. However, the distribution of C.O. within the optic laminae was not uniform. Within the main optic layers, the SFGS, four metabolically distinct sublaminae were distinguished and designated from superficial to deep as sublaminae a, b, c, and d. The most intense reactivity was localized within SFGSa and SFGSd, followed by SFGSb, then SFGSc. In SFGSd, intense reactivity was found to occur specifically within a class of large diameter axons and terminals that were apparently optic since these were also labeled with HRP and cobaltous lysine applied to the optic nerve. Regional C.O. differences across the tectum were also noted. Low levels were found in neurons and optic terminals along the growing immature medial, lateral, and posterior edges of tectum, but were higher at the more mature anterior pole and central regions of tectum. This suggests that the oxidative metabolic activity is initially low in newly formed tectal neurons and optic axons, but gradually increases with neuronal growth and functional axon terminal maturation. Most C.O. staining was localized within neuropil, whereas the perikarya of most tectal neurons were only lightly reactive. Only a few neuron classes, mostly the relatively larger projection neurons, had darkly reactive perikarya.In the retina, intense C.O. reactivity was localized within the inner segments of photoreceptors, the inner and outer plexiform layers, and within certain classes of bipolar and ganglion cells. The large ganglion cells in particular were intensely reactive. Like the large diameter optic terminals in SFGSd, the large ganglion cells were preferentially filled with HRP, suggesting that they may project to tectum and are the source of the darkly reactive large diameter axons and terminals in sublamina SFGSd.We propose a new scheme to describe tectal lamination that integrates laminar differences in C.O. reactivity with classical histological work. We further suggest that these laminar patterns represent a functional substratification of the classically defined tectal laminae and, in particular, suggest that different optic sublaminae may be innervated by different classes of ganglion cells.
Immunohistochemical localization of a membrane‐associated, 4.1‐like protein in the rat visual cortex during postnatal development
Authors: Tsumoto T. , Sato H. , Sobue K. 
Published: January 2005

AbstractExpression and localization of a membrane‐associated protein, an analog of erythrocyte protein 4.1, in the visual cortex were immunohistochemically studied in the rat, ranging in age from newborn to adult. In the adult, dendrites and somas of layer V pyramidal cells were stained by the antiprotein 4.1 antibody. In most of these immunoreactive neurons, the plasma membrane seemed to be preferentially stained. Neurons located in layers II and III of the cortex were only faintly stained, and those in layers IV and VI were not stained. At birth, the immunoreactivity was already present in pyramidal cells located in the upper part of the cortical subplate. Immature neurons located in the cortical plate were not stained by the antibody, suggesting that the 4.1‐like protein is expressed only in the neurons that have differentiated or are differentiating.At postnatal days 2–8, immunoreactive neurons were dramatically increased in layers V and VI and intense labeling was seen at the apical dendrites of layer V pyramidal cells. Most of the stained processes of these and other neurons showed a sign of rapid dendritic growth, i.e., growth cones and filopodia. At days 10–17, the basal dendrites of pyramidal cells in layers II and III became detectable, although still slender. At days 20–37, these dendrites in layers II, III, and V became intensely immunoreactive, and dendritic spines were visualized by the antibody. Throughout all the ages, axons of neurons and neuroglia were not stained by the antibody. Also, most of the neurons in layer IV of the cortex were not immunoreactive.These results suggest that the 4.1‐like protein is abundantly expressed in growing parts of the dendrites and spines. A hypothesis that this protein may play a role in synaptic plasticity in the developing visual cortex is discussed.