bluuebunny/crossref_metadata_2025_split huggingface dataset:
Plasticity of frequency organization in auditory cortex of guinea pigs with partial unilateral deafness
Authors: Robertson Donald , Irvine Dexter R. F. 
Published: January 2005

AbstractWe have examined the effect of restricted unilateral cochlear lesions on the orderly topographic mapping of sound frequency in the auditory cortex of adult guinea pigs. These lesions, although restricted in spatial extent, resulted in a variety of patterns of histological damage to receptor cells and nerve fibres within the cochlea. Nevertheless, all lesions resulted in permanent losses of sensitivity of the cochlear neural output across a limited frequency range. Thirty‐five to 81 days after such damage to the organ of Corti, the area of contralateral auditory cortex in which the lesioned frequency range would normally have been represented was partly occupied by an expanded representation of sound frequencies adjacent to the frequency range damaged by the lesion. The thresholds at their new characteristic frequencies (CFs) of clusters of cortical neurones in these regions were close to normal thresholds at those frequencies (mean difference across all animals was 3.8 dB). In a second series of experiments, the responses of neurone clusters were examined within hours of making similar cochlear lesions. It was found that shifts in CF toward frequencies spared by the lesions could occur, but thresholds were greatly elevated compared to normal (mean difference was 31.7 dB in five animals). The emergence of sensitive drive in such regions after prolonged recovery periods in lesioned animals thus suggests that the auditory cortical frequency map undergoes reorganization in cases of partial deafness. Some features of this reorganization are similar to changes reported in somatosensory cortex after peripheral nerve injury, and this form of plasticity may therefore be a feature of all adult sensory systems.
Survey of noncortical afferent projections to the basilar pontine nuclei: A retrograde tracing study in the rat
Authors: Mihailoff G. A. , Kosinski R. J. , Azizi S. A. , Border B. G. 
Published: January 2005

AbstractThe retrograde transport of the conjugate wheat germ agglutinin–horseradish peroxidase (WGA‐HRP) was used in the rat to identify the cell bodies of origin for all subcortical projections to the basilar pontine nuclei (BPN). A parapharyngeal surgical approach was used to allow the injection micropipette to enter the BPN from the ventral aspect of the brainstem and thus avoid any potential for false‐positive labeling due to transection and injury‐filling of axonal systems located dorsal to the basilar pontine gray.A surprisingly large number of BPN afferent cell groups were identified in the present study. Included were labeled somata in the lumbar spinal cord and a large variety of nuclei in the medulla, pons, and midbrain, as well as labeled cells in diencephalic and telencephalic nuclei such as the zona incerta, ventral lateral geniculate, hypothalamus, amygdala, nucleus basalis of Meynert, and the horizontal nucleus of the diagonal band of Broca.Quite a number of cell groups known to project directly to the cerebellum also exhibited labeled somata in the present study. To explore the possibility that such neurons were labeled because their axons were transected and injury‐filled as they coursed through the BPN injection site to enter the cerebellum via the brachium pontis, a series of rats received complete, bilateral lesions of the brachium pontis followed 30‐60 minutes later with multiple, diffuse injections of WGA‐HRP (12‐16 placements per animal) throughout the cerebellar cortex. In another series of animals, the massive cerebellar WGA‐HRP injections were not preceded by brachium pontis lesions. In the latter cases, each of the cell groups in question that were known to project directly to the cerebellum exhibited labeled somata. However, when the cerebellar HRP injections were preceded by brachium pontis lesions, each of the cell groups in question continued to exhibit labeled somata in numbers comparable to that observed in the nonlesion cases. This implies that such neurons project to the BPN and the cerebellar cortex and that the axons of these particular neurons do not project to the cerebellum via the brachium pontis.
Collateral projections of predorsal bundle cells of the superior colliculus in the rat
Authors: Bickford Martha E. , Hall William C. 
Published: January 2005

AbstractThe deep layers of the superior colliculus contain cells which are premotor in the sense that they respond prior to the onset of shifts in gaze and send axons, by way of a pathway called the predorsal bundle, to the contralateral brainstem gaze centers and cervical spinal cord. Previous studies have suggested that these cells also contribute to other efferent pathways which arise in the deep layers. The present study examines the contributions of the cells of origin of the predorsal bundle to these additional pathways as a step toward understanding their roles in gaze mechanisms. In one series of experiments, retrograde tracers were used to compare the laminar distribution of predorsal bundle cells with the distributions of the cells of origin of three other pathways: those that project to the intralaminar region of the dorsal thalamus, those that project to the contralateral superior colliculus, and those that project to the ipsilateral brainstem tegmentum. Predorsal bundle cells were found primarily in stratum griseum intermedium sublayer b. This distribution overlaps extensively with the distribution of colliculus cells that project to the intralaminar region of the thalamus. In contrast, the majority of the colliculus cells that project to either the contralateral superior colliculus or the ipsilateral brainstem tegmentum do not overlap extensively with the predorsal bundle cells; instead, they are primarily located dorsal or ventral to sublayer b of stratum griseum intermedium. In a second series of experiments, two regions were injected with different retrograde fluorescent tracers in single animals in order to study the collateral projections of the cells of origin of these pathways. The results indicate that many predorsal bundle cells project to the intralaminar region of the dorsal thalamus but that only a few contribute to the tectotectal pathway. The results also indicate that few tectotectal cells contribute to the ipsilateral tectobulbar pathway.
Bed nucleus of the stria terminalis: Cytoarchitecture, immunohistochemistry, and projection to the parabrachial nucleus in the rat
Authors: Moga Margaret M. , Saper Clifford B. , Gray Thackery S. 
Published: January 2005

AbstractThe bed nucleus of the stria terminalis (BST) sends a dense projection to the parabrachial nucleus (PB) in the pons. The BST contains many different types of neuropeptidelike immunoreactive cells and fibers, each of which exhibits its own characteristic distribution within cytoarchitecturally distinct BST subnuclei. Corticotropin releasing factor (CRF)‐, neurotensin (NT)‐, somatostatin (SS)‐, and enkephalin (ENK)‐like immunoreactive (ir) neurons are particularly numerous within areas of the BST that project to the PB. In this study, we use the combined retrograde fluorescence‐immunofluorescence method to determine whether neurons in the BST that project to the PB contain these immunoreactivities. After Fast Blue injections into PB, retrogradely labeled neurons were numerous throughout the lateral part of the BST, particularly in the dorsal lateral (DL) and posterior lateral subnuclei. Retrogradely labeled neurons were also present in the preoptic, ventral lateral, and supracapsular BST subnuclei and in the parastrial nucleus. Many of the CRF‐ir, NT‐ir, and SS‐ir neurons in DL were retrogradely labeled. A few double‐labeled cells of each type were also found in the posterior lateral, ventral lateral and supracapsular BST subnuclei ENK‐ir neurons were never retrogradely labeled. Our results show that BST neurons that project to the PB stain for the same neuropeptides as those in the central nucleus of the amygdala (CeA) that project to the PB, demonstrating further the close anatomical relations between these two structures.
Morphology and distribution of neurons in the retina of the american garter snake Thamnophis sirtalis
Authors: Wong R. O. L. 
Published: January 2005

AbstractAmerican garter snake Thamnophis sirtalis, retina correspond to the retinal mosaic viewed in the living eye (Land and Snyder, Vision Res. 11:105–114, '85). The garter snake has three major morphological types of cones; large single cones, small single cones, and double cones. The brightly reflecting components seen in the living eye are large single cones and principal cones of double cones, whereas irregularly spaced dark regions within this mosiac mark the positions of small single cones. The “sparkle” of the retinal mosaic originates from the ellipsoid region of the cones where microdroplets of high refractive index are densely packed. Unlike conventional oil droplets, these microdroplets reside adjacent to mitochondrial cristae within the ellipsoid. However, the microdroplets may function collectively as a single large oil droplet to increase the angular sensitivity of the inner segments, thus reducing a potentially large Stiles–Crawford effect predicted for this geometrically small eye.The ganglion cell layer of the garter snake comprises two morphologically distinct populations of presumed neurons; classical neurons and microneurons. Density distribution maps for neurons in the ganglion cell layer and the photoreceptor layer reveal the presence of a putative area centralis and a horizontal visual streak. The topography of large cones parallels that of classical neurons. Small single cones have a more circular distribution, but also peak in density at the area centralis. The convergence of cones to classical neurons is lowest at the area centralis, 2.5:1, and highest, 4:1, at the retinal edge.With its interesting structural features, the garter snake retina provides helpful insight into different strategies in eye design.
Retrograde double‐labeling study of the marnmillothalamic and the mammillotegmental projections in the rat
Authors: Hayakawa Tetsu , Zyo Katuya 
Published: January 2005

AbstractCollateral axonal branching from the medial or lateral mammillary nuclei to the anterior thalamus, Gudden's tegmental nuclei, the nucleus reticularis tegmenti pontis, and the medial pontine nucleus was studied using the fluores‐ cent retrograde double‐labeling method. One day after injection of Fast Blue into the anterior thalamic nuclei or Gudden's tegmental nuclei, Nuclear Yel‐ low was injected into Gudden's tegmental nuclei or the nucleus reticularis teg‐ menti pontis and the medial pontine nucleus. Following 1day survival, single‐ and double‐labeled neurons were examined in the mammillary nuclei.The lateral mammillary nucleus contains neurons whose collateral fibers project to both the dorsal tegmental nucleus of Gudden and the ipsilateral or contralateral anterodorsal thalamic nucleus, to both the medial pontine nucleus and the anterodorsal thalamic nucleus, and to both the dorsal tegmen‐ tal nucleus of Gudden and the medial pontine nucleus. The pars medianus and pars medialis of the medial mammillary nucleus contain neurons whose collat‐ eral fibers project to both the anteromedial thalamic nucleus and the ventral tegmental nucleus of Gudden, to both the anteromedial thalamic nucleus and the medial part of the nucleus reticularis tegmenti pontis, and to both the ven‐ tral tegmental nucleus of Gudden and the medial part of the nucleus reticu‐ laris tegmenti pontis. The dorsal half of the pars posterior of the medial mam‐ millary nucleus contains a few neurons whose collateral fibers project to both the anteromedial thalamic nucleus and the rostral part of the ventral tegmen‐ tal nucleus of Gudden, and to both the caudal part of the anteroventral thal‐ amic nucleus and the rostral part of the ventral tegmental nucleus of Gudden, while the pars lateralis of the medial mammillary nucleus contains no double‐ labeled neurons and projects only to the anteroventral thalamic nucleus.
Anatomical study of the final common pathway for vocalization in the cat
Authors: Holstege Gert 
Published: January 2005

AbstractVocalization, the nonverbal production of sound, can be elicited in many vertebrates by stimulation in several regions of the limbic system but most easily in the caudal periaqueductal gray (PAG). This study shows that a specific cell group in the lateral part of the caudal PAG and in the tegmentum just lateral to it projects bilaterally to the nucleus retroambiguus (NRA) in the caudal medulla oblongata. Similar but much weaker projections are derived from the dorsal PAG. Neurons in the NRA in turn project via a contralateral pathway through the ventral funiculus of the spinal cord to motoneuronal cell groups, innervating intercostal and abdominal muscles. These projections are stronger on the contralateral side, although at lower thoracic and upper lumbar levels, many fibers recross to terminate in the ipsilateral motoneuronal cell groups. In the brainstem NRA neurons project to the motoneuronal cell groups innervating mouth‐opening and perioral muscles as well as to motoneurons innervating the pharynx, soft palate, and tongue, and probably to the larynx. All these muscles are active in vocalization. The present anatomical results, combined with the physiological results of others, indicate that the projections from PAG via NRA to vocalization motoneurons from the final common pathway in vocalization. The role of this pathway in the total framework of emotional behavior is discussed.
Generation of monoclonal antibodies against a nematode peptide extract: Another approach for identifying unknown neuropeptides
Authors: Sithigorngul Paisarn , Cowden Cynthia , Guastella John , Stretton Antony O.W. 
Published: January 2005

AbstractMonoclonal antibodies that cross‐react with Ascaris neural antigens were generated in mice immunized with a conjugate made with keyhole limpet hemocyanin (KLH) linked to a crude peptide extract from Caenorhabditis elegans. The response to KLH was suppressed by injection of cyclophosphamide 3 days after immunization with a gamma‐aminobutyric acid (GABA)‐KLH conjugate. Screening of hybridomas was carried out by enzyme‐linked immunosorbent assay and whole mount immunocytochemistry. Two similar clones produced antibodies that recognized a small subset of Ascaris neurons. This result suggests that the monoclonal antibody technique might be useful for identifying new neuropeptides since the antibodies can be used for localization of the neuropeptidelike substances and, potentially, for immunoaffinity chromatography. As a by‐product of this experiment, monoclonal antibodies that recognize GABA‐like immunoreactivity in whole mounts and plastic sections were also obtained.
Development of the rat thalamus: V. The posterior lobule of the thalamic neuroepithelium and the time and site of origin and settling pattern of neurons of the medial geniculate body
Authors: Altman Joseph , Bayer Shirley A. 
Published: January 2005

AbstractLong‐survival, sequential, and short‐survival thymidine radiograms of rat embryos, fetuses, and young pups were analyzed in order to examine the time of origin, site of origin, migratory route, and settling pattern of neurons of the medial geniculate body (MG). Quantitative evaluation of long‐survival radiograms established that the bulk of MG neurons are generated between embryonic (E) days E13 and E15, with a pronounced peak on day E14. There is an overall lateral‐to‐medial and caudal‐to‐rostral chronological gradient in MG neurogenesis. On the basis of significant regional differences in the birth dates of neurons, the MG was divided into several chronoarchitectonic areas. The earliest‐generated neurons (with close to 20% of the cells produced on day E13 and a negligible proportion on day E15) form the dorsal and ventral clusters far laterally. Next in sequential order are the neurons of the lateral shell, intermediate shell, and medial shell of the MG. The medial shell with it latest‐generated neurons (with over 30% produced rostrally on day E15) corresponds to the medial (magnocellular) subnucleus of the MG. There were no neurogenetic differences between the traditional dorsal and ventral divisions of the MG.Examination of sequential radiograms in rats labeled with 3H‐thymidine on day E14 or E15 and killed on successive days brought supportive evidence for our earlier identification, in short‐survival radiograms, of a posteroventral thalamic neuropithelial evagination as the putative source, or committed cell line, of MG neurons. Wave fronts of apparently migrating unlabeled and labeled cells could be traced from this sublobule in a posterolateral direction to the future site of the MG.
Interaction between cholinergic neurons and substance P or calcitonin gene‐related peptide terminals of the rat sacral intermediolateral nucleus: Double immunostaining at the light and electron microscopic levels
Authors: Peng Yuwen , Kohno Johji , Shinoda Koh , Kawai Yoshinori , Ono Keiro , Jiang Wenhua , Shiotani Yahe 
Published: January 2005

AbstractThe relationships both between cholinergic neurons and substance P (SP) and between cholinergic neurons and calcitonin gene‐related peptide (CGRP) terminals were examined in the rat sacral intermediolateral nucleus at the light and electron microscopic levels by means of double‐immunostaining methods. Cholinergic neurons were labeled by a monoclonal antibody to choline acetyltransferase (CAT) with the avidin‐biotin technique and stained bluish‐green by indolyl‐β‐galactoside reaction products with β‐galactosidase as a marker. On the same sections, SP or CGRP fibers were labeled by polyclonal antisera to SP or CGRP after application of the peroxidase‐antiperoxidase (PAP) method and stained brown by the p‐dimethylaminoazobenzene (DAB) reaction. After embedding in Epon, light and electron microscopic sections were examined. At the light microscopic level, CGRP‐like immunoreactive (CGRP‐I) fibers and SP‐like immunoreactive (SP‐I) fibers were found to pass through the lateral edge of the dorsal horn and then into the dorsal region of the sacral intermediolateral nucleus. In addition, SP‐I fibers also extend from the dorsolateral funiculus into the entire sacral intermediolateral region. At the electron microscopic level, many axosomatic and axodendritic synapses were found between CAT‐I structures and SP‐I terminals in the intermediolateral nucleus, whereas most of the CGRP‐I terminals in this area made axodendritic synapses with CAT‐I dendrites. These results indicate that cholinergic neurons in the sacral intermediolateral nucleus receive direct synaptic input from SP‐I and CGRP‐I terminals. Therefore, it is likely that both SP‐I and CGRP‐I fibers from dorsal root ganglia and intrinsic SP‐I fibers make direct synapses with sacral parasympathetic preganglionic neurons and thus have great importance in the control of bowel and bladder reflexes.
Beta‐endorphin and gonadotropin‐releasing hormone synaptic input to gonadotropin‐releasing hormone neurosecretory cells in the male rat
Authors: Chen Wen‐Pin , Witkin Joan W. , Silverman Ann‐Judith 
Published: January 2005

AbstractPhysiological and pharmacological evidence has suggested that both endogenous opiates and gonadotropin‐releasing hormone (GnRH) itself can act centrally to exert a tonic inhibition on gonadotropin secretion via an inhibition of the neurosecretion of GnRH. To determine if the effects of these two peptides might be mediated via a direct synaptic input to the GnRH neuron, we undertook a double label ultrastructural study. We were able to localize in the same tissue section beta‐endorphin and GnRH. Analysis of serial sections through GnRH perikarya and dendrites in the male rat diagonal band/preoptic area revealed that almost 10% of the synapses impinging on the GnRH neuron contained beta‐endorphin; an additional 10% of the terminals contained GnRH. These data provide anatomical evidence in support of both a direct modulation of GnRH release by opiates and of the presence of an ultrashort feedback loop.
Alpha and delta ganglion cells in the rat retina
Authors: Peichl Leo 
Published: January 2005

AbstractIn the rat retina a distinctive class of large ganglion cell was demonstrated by intracellular staining with Lucifer Yellow and with reduced silver staining. They are referred to as alpha cells because they resemble the alpha cells of other mammalian retinae. A second class, called delta cells, is also described. Both classes belong to the type I group defined by Perry (Proc. R. Soc. Lond. [Biol.] 204:363–375, '79). The dendritic trees of both classes stratify in either an inner or outer lamina of the inner plexiform layer which presumably corresponds to an on/off dichotomy in the response to light.Rat alpha cells constitute 2–4% of all ganglion cells, and their density, size, and detailed morphological appearance change with retinal location. Inner and outer stratifying alpha cells of the rat show significant differences compared to those of other mammals. In central retina (at the large cell density maximum) the densities and dendritic field sizes of inner and outer alpha cells are approximately equal. However, in peripheral retina outer alpha cells are up to three times more numerous and have dendritic field areas only one‐third the size of those of the inner alpha cells. The maximal density is about 110 alpha cells/mm2; peripheral densities are about 30/mm2. The smallest central dendritic field diameters are 220 μm. Peripheral dendritic field diameters are 350–550 μm for outer and 570–790 μm for inner alpha cells. Each subpopulation is distributed in a regular mosaic, and the territorial arrangement of the dendritic fields provides a homogeneous coverage of the retina. The dendritic coverage is three‐ to 3.6‐fold for each subpopulation, irrespective of their other quantitative differences. Eccentricity‐dependent receptive field sizes of the alpha cells are predicted from the morphological data.
Sound‐generating (sonic) motor system in a teleost fish (Porichthys notatus): Sexual polymorphisms and general synaptology of sonic motor nucleus
Authors: Bass Andrew H. , Marchaterre Margaret A. 
Published: January 2005

AbstractThe sonic motor nucleus of the plainfin midshipman, Porichthys notatus, is a midline nucleus located at the junction of the caudal medulla and rostral spinal cord. Its motoneurons innervate sonic “drumming” muscles that are attached to the lateral walls of the swimbladder. There are two classes of sexually mature males referred to as Type I and Type II. The Type I males are larger and generate sounds during the breeding season. The Type II males are smaller and, like adult females, have not yet been shown to generate sounds. This study examined possible sex differences in the size of sonic motoneurons, and the type and distribution of their afferent terminal boutons.The average soma diameter of motoneurons of Type I males is about 50% larger than that of Type II males and females. There is also a small but significant difference in soma diameter between Type II males and females; they are smaller in the former class.There were no sex differences in the presence or distribution of different classes of axosomatic and axodendritic terminal boutons, which included: (1) active zones with either clear, round, or pleomorphic vesicles, (2) active zones with both clear, round vesicles, and larger dense core vesicles, and (3) “mixed synapses” with gap junctions and active zones usually associated with pleomorphic vesicles.The results are discussed within the context of sexual differentiation of vertebrate motor systems and the functional organization of the sonic motor system in fishes. Sex differences in soma diameter correlate with a number of sex differences in the gross and ultrastructural features that distinguish the sonic muscles of Type I males from those of Type II males and females, which are similar to each other. The absence of qualitative sex differences in synaptic morphology suggest that the central neuronal circuitry of the sonic motor system is similar among all three adult morphs.