bluuebunny/crossref_metadata_2025_split huggingface dataset:
Projections from the cochlear nucleus to the inferior colliculus in normal and neonatally cochlea‐ablated gerbils
Authors: Moore David R. , Kitzes Leonard M. 
Published: May 2005

AbstractThe distribution of the projection from one cochlear nucleus (CN) within each inferior colliculus (IC) was studied in adult, normal gerbils and adult gerbils subjected to unilateral ablation of the contralateral cochlea at 2 days of age. The projection was studied by using the Fink‐Heimer technique for impregnating degenerating axons and their terminal processes with silver. Following an extensive, unilateral lesion of the CN, degeneration was seen in both ICs of all animals. In normal animals, degeneration was both more widespread and heavier in the contralateral than in the ipsilateral central nucleus of IC (ICC). Degeneration was most widespread in the rostral and lateral parts of both ICCs and in the ventral part of the contralateral ICC. Degeneration was observed in 26% of the area examined in ipsilateral ICC and in 73% of the area examined in contralateral ICC. In cochlea‐ablated animals there was a much greater similarity in the area of degeneration in the ICC ipsilateral (57%) and contralateral (67%) to the CN lesion. The same regional distributions of degeneration were observed as in the normal animals except that the distribution of degeneration in the ipsilateral ICC more closely resembled the normal contralateral than the normal ipsilateral profile. We conclude that the normal distribution of projections from the CN within the ipsilateral ICC is substantially modified by neonatal ablation of the contralateral chochlea.
A quantitative electron microscope study of the perikaryal projections of sensory ganglion neurons. II. Gecko and lizard
Authors: Pannese Ennio , Bianchi Rossella , Gioia Magda , Ventura Raoul 
Published: May 2005

AbstractThe perikaryal projections of the neurons in the thoracic spinal ganglia of gecko and lizard usually appear as finger‐shaped evaginations running roughly parallel to the surface of the nerve cell body; they show a nearly circular cross section with a rather uniform transverse diameter having an average value of about 0.2 μm. In both gecko and lizard a very high correlation was found between the surface area of perikaryal projections and both the volume and smoothed surface area of the corresponding nerve cell body.The results of the present research agree with those obtained in a previous study on two mammal species (cat and rabbit) and lend further support to the hypothesis advanced in that study; i.e., that perikaryal projections in sensory ganglion neurons are normal formations which maintain the surface‐to‐volume ratio above the critical level for metabolic exchanges.Perikaryal projections increase the surface area of the nerve cell body by 32.5% in gecko and 30% in lizard, while they increase it by 43% in cat and 39.5% in rabbit. This difference may be related to the lower metabolic rate of the neurons in poikilotherms than in mammals.
Somatostatin receptors: Distribution in rat central nervous system and human frontal cortex
Authors: Uhl George R. , Tran Vinh , Snyder Solomon H. , Martin Joseph B. 
Published: May 2005

AbstractSomatostatins are a brain peptide family centered on a 14‐amino acid cyclic peptide (SS‐14) and a 28‐amino acid N‐terminally extended form (SS‐28). Using radioiodinated analogs of SS‐14 and SS‐28, we have identified specific binding sites in rat and human brain sections that display pharmacological properties anticipated for somatostatin receptors and discrete patterns of anatomical localization. High binding densities are found in many forebrain regions, with special densities in infragranular cerebral cortical laminae in rat and human brain. In the rat, other densities lie in olfactory zones, lateral and triangular septal nuclei, the CA‐1 hippocampal region, and claustrum with moderate densities in the striatum. Discrete hypothalamic areas, especially the median preoptic, paraventricular, and periventricular nuclei, display elevated binding levels, while the thalamus shows only scattered areas of modest binding. Midbrain receptor concentrations are found in portions of the periaqueductal gray, interpeduncular nucleus, and the substantia nigra. Notable pontine and medullary densities lie in the locus coeruleus, fourth ventricular floor, parabrachial, solitary, prepositus hypoglossal, dorsal column, and caudal trigeminal zones. Although the cerebellar cortex shows unimpressive densities, each of the deep cerebellar nuclei is heavily labeled. Modest spinal cord receptor densities are concentrated in the substantia gelatinosa and central cord regions.These localizations show many parallels with the distributions of SS‐immunoreactive neurons, fibers, and terminals determined previously by immunohistochemistry. They provide plausible loci for several reported physiological or pharmacological activities of the SS‐peptides, and may improve understanding of the role of the SS alterations described in several human neurodegenerative disorders.
Topographic organization of the optic radiation of the cat
Authors: Nelson Sacha B. , Le Vay Simon 
Published: May 2005

AbstractPairs of injections of different neuroanatomical tracers–peroxidase‐conjugated wheat‐germ agglutinin (WGA) and [3H]proline–were made into the lateral geniculate nucleus (LGN) of the cat, and the course of the labeled fibers in the optic radiation was reconstructed. When the two injections were widely separated in the rostrocaudal dimension of the LGN (i.e., one in the representation of the lower quadrant of the visual field and one in the upper quadrant), the two sets of labeled fibers also remained separated in the long (roughly rostrocaudal) axis of the optic radiation. When the injections were widely separated in the mediolateral dimension of the LGN (i.e., one at the representation of the area centralis and one on the horizontal meridian in the far periphery of the field), the two sets of labeled fibers were separated in the short (mediolateral) dimension of the radiation. Shortly before reaching area 17, however, the medially and laterally placed fibers exchanged positions. This crossing is the basis of the topological inversion in the optic radiation deduced previously by Connolly and Van Essen (J. Comp. Neurol. 226:544–564, '84). The retinotopic organization of fibers in the radiation is less precise (in either dimension) than that of their terminal arborizations in visual cortex, but even injections as close as 1 mm to each other gave rise to spatially distinct fiber distributions. The WGA injections also labeled the corticogeniculate fibers by retrograde transport; these fibers traveled in a separate pathway medial to the optic radiation.
Selective retrograde labeling with D‐[3H]‐aspartate in afferents to the mammalian superior colliculus
Authors: Matute Carlos , Streit Peter 
Published: May 2005

AbstractThe selectivity previously reported for retrograde labeling patterns obtained following D‐[3H]‐aspartate injections and proposed to be related to the transmitter specificity of the labeled pathways was tested in afferents to the superior colliculus (SC) of rats and rabbits.In rats selectivity was assessed by comparing retrograde perikaryal labeling patterns observed in D‐[3H]‐aspartate experiments with those found after administration of a nonselective tracer, horseradish‐peroxidase‐labeled wheat germ agglutinin (HRP‐WGA), and of the tritiated neurotrasmitter γ‐aminobutyric acid (GABA). Following D‐[3H]‐aspartate injections into the SC labeling was intense in a large number of cortical and hypothalamic neurons. Other afferents to the SC, however, such as those originating from the ventrolateral geniculate nucleus, the pars reticulata of the substantia nigra, the locus coeruleus, the pontine nuclei, or the retinal ganglion cells, were not labeled. Similar results were obtained in rabbits.In cats, the analysis was focused on the cerebral cortex, since in an earlier investigation no retrograde labeling had been detectedin the visual cortex following D‐[3H]‐aspartate injectionsin the SC. In the present work, however, retrogradely labeled neuronswere observed in various cortical areas including a few in visual cortex.This report shows selective retrograde labeling for a part of the afferents to the SC. This selectivity does not display major differences among the mammalian species studied. Moreover, according to the information available about the distribution of neurotransmittersin the brain, the findings reported here favour the idea that D‐[3H]‐aspartate is a retrograde tracer selective for glutamatergic and/or aspartatergic pathways.
The structure of the brainstem and cervical spinal cord in lungless salamanders (family plethodontidae) and its relation to feeding
Authors: Roth Gerhard , Wake David B. 
Published: May 2005

AbstractWe present an HRP study of the sensory tracts and motor nuclei associated with feeding (especially use of the tongue) in plethodontid salamanders (mainly Batrachoseps attenuatus, Bolitoglossa subpalmata, Desmognathus ochrophaeus, Eurycea bislineata, and Plethodon jordani). The nerves studied are VII (ramus hyomandibularis only), IX, X, XI, the first spinal nerve (hypoglossus), and the second spinal nerve. Two types of sensory projections are universally found in the brainstem: superficial somatosensory projections of VII, IX, and X, and deeper visceral sensory projections of IX and X to the fasciculus solitarius. The first spinal nerve and the spinal accessory nerve (XI) have no sensory projections, but the second spinal nerve has typical projections along the dorsal funiculus of the spinal cord.The motor nuclei of VII ramus hyomandibularis, IX, and X form a combined nucleus situated at the level of the IX/X root complex. The nucleus of the first spinal nerve is well separated from the combined nucleus and is situated rostral and caudal to the obex. The rostral part of the motor nucleus of the second spinal modestly overlaps that of the first. The motor nucleus of the spinal accessory nerve is more or less restricted to the region of the second spinal nerve. Its fibers leave the brain through the last root of the IX/X complex and the related ganglion. Bolitoglossine and nonbolitoglossine differ in the architecture of the spinal nuclei. Two distinct types of motor neurons occur in spinal nuclei of nonbolitoglossine species–some of those with tongue projection–but only one type is found amongthe tongue‐projecting bolitoglossine group.
The development of the dentate area and the hippocampal mossy fiber projection of the rat
Authors: Gaarskjaer Frank B. 
Published: May 2005

AbstractThe development of the dentate area and the hippocampal mossy fiber system of the rat has been investigated at the light microscopic level by using fluorescent tracing, Nissl, and Timm's histochemical methods. Although the cytoarchitectonic development of the dentate granular layer is mainly a postnatal phenomenon, the initial events take place before birth. The aggregation and maturation of the cells in the granular layer proceed in a graded fashion from the lateral to the medial and from the superficial to the deep aspects of the layer. The earliest‐formed granule cells are probably derived directly from the cells of the ventricular zone. They start to form mossy fibers prenatally, either during the relatively long period of migration to the granular layer or soon after their arrival. However, most of the granule cells are derived from a secondary proliferative center in the hilus. They start to produce mossy fibers postnatally a while after arriving at the granular layer. The total complement of granule cells starts to grow mossy fibers in a sequence that is related to the final position of the cells of origin within the granular layer. This sequence also proceeds in a graded fashion from the lateral to the medial and from the superficial to the deep aspects of the layer.In the beginning the mossy fibers elongate relatively rapidly. Already at birth the Timm‐stained mossy fiber zone occupies the anterolateral part of the hilus and the adjacent suprapyramidal parts of the regio inferior. Once the mossy fibers have reached the distal end of the regio inferior they elongate along the longitudinal axis of the hippocampus more slowly. At the same time the Timm‐stainability of the mossy fiber zone, which, during the first postnatal week, is weaker toward the regio superior, develops a mature pattern in which the distal part of the zone stains most intensely. Throughout development, fibers from the granule cells that form first are longer and diverge more in the septotemporal dimension than fibers from later‐forming granule cells. In contrast to other axonal systems which appear to be sculptured from a diffuse set of connections the results presented here provide evidence that the topographic relationships of the mossy fiber system develop in a stepwise fashion.
The projection of the visual field onto the lateral geniculate nucleus of the ferret
Authors: Zahs Kathleen R. , Stryker Michael P. 
Published: May 2005

AbstractThe projection of the visual field onto the dorsal lateral geniculate nucleus (LGN) of the ferret was mapped electrophysiologically. The nucleus contains a single orderly map of the contralateral visual hemifield. The upper visual field is represented dorsally and rostrally in the nucleus; central fields are found in the medial and caudal sections of the LGN; and peripheral fields are represented most laterally. The ipsilateral eye is represented in laminae Al and Cl up to eccentricities of 20–30°. Lines of projection run perpendicular to the laminar borders. The ferret LGN resembles that of the cat rotated approximately 110° clockwise in the sagittal plane, viewing the right nucleus from its lateral aspect; it differs from the cat in having a larger monocular segment.
An autoradiographic study of projections ascending from the midbrain central gray, and from the region lateral to it, in the rat
Authors: Eberhart J. A. , Morrell J. I. , Krieger M. S. , Pfaff D. W. 
Published: May 2005

AbstractAscending projections from the midbrain central gray (CG) and from the region lateral to it were traced in the rat using tritiated amino acid autoradiography. Leucine or a cocktail of amino acids (leucine, proline, lysine, histidine, and tyrosine) were used as tracers.In addition to projections within the midbrain, ascending fibers follow three trajectories. The ventral projection passes through the ventral tegmental region of Tsai and the medial forebrain bundle to reach the hypothalamus, preoptic area, caudoputamen, substantia innominata, stria terminalis, and amygdala. There are labeled fibers in the diagonal bands of Broca and medial septum, and terminal labeling in the lateral septum, nucleus accumbens, olfactory tubercle, and frontal cortex. The dorsal periventricular projection terminates in the midline and intralaminar thalamic nuclei. The ventral periventricular projection follows the ventral component of the third ventricle into the hypothalamus, passing primarily through the dorsal hypothalamic area and labeling the rostral hypothalamus and preoptic area.Projections from the region lateral to the CG are similar, but exhibit stronger proximal, and weaker distal, projections. Rostral levels of the CG send heavier projections to the fields of Forel and the zona incerta, but fewer fibers through the supraoptic decussation, than do caudal levels.Ascending projections from the CG are both strong and widespread. Strong projections to the limbic system and the intralaminar thalamic nuclei provide an anatomical substrate for CG involvement in nociception and affective responses.
Vasoactive intestinal polypeptide and substance P in primary afferent pathways to the sacral spinal cord of the cat
Authors: Kawatani Masahito , Erdman Susan L. , de Groat William 
Published: May 2005

AbstractAn analysis of vasoactive intestinal polypeptide immunoreactivity (VIP‐IR) and substance P‐IR in the cat spinal cord has revealed marked differences in the distribution of the two peptides. While substance P‐IR was located at all levels of the cord, VIP‐IR was most prominent in the sacral segments in Lissauer's tract and lamina I on the lateral edge of the dorsal horn. VIP‐IR was also present in the sacral cord in (1) laminae V, VII, and X, (2) a thin band on the medial side of the dorsal horn, (3) the dorsal commissure, (4) the lateral band of the sacral parasympathetic ucleus, and (5) in a few animals in Onuf's nucleus. In other segments of the spinal cord VIP‐IR was much less prominent but was present in Lissauer's tract and laminae I, II, and X. Substance P‐IR was more uniformly distributed at all segmental levels in laminae I–III, V, VII, and X and in the dorsal commissure.In ventrolateral lamina I of the sacral spinal cord both VIP‐IR and substance P‐IR exhibited a distinctive periodic pattern in te rostrocaudal axis. The peptides were associated with bundles of dorsoventrally oriented axons and varicosities spaced at approximately 210‐μm intervals center to center along the length of the spinal cord. The bundles in lamina I continued into lamina V where they further divided into smaller bundles that extended medially through laminae V and VII. The most prominent bundles of VIP axons passed ventrally from lateral laminae V and VII to enter lamina X and the ventral part of te dorsal gray commissure. On the other hand the maority of substance P axons in lamina V turned dorsally to join wth axons on the medial side of the dorsal horn and to pass into the dorsal part of the dorsal gray commissure. Rostrocaudal VIP axons were present not only in Lissauer's tract but also in dorsolateral lamina I, in the lateral funiculus and in the ependymal cell layer of the central canal.Following unilateral transectionofthe sacral dorsal roots (2 weeks–22 months) the density of VIP axons and terminals was markedly reduced in ipsilateral Lissauer's trat and lateral laminae I and V; however, no change was detected in lamina X. Sacral deafferentation reduced substance P‐IR in the dorsal gray commissure and in lateral laminae I and V.It is concluded that VIP‐IR and substance P‐IR are present at all levels of the cat spinal cord, but that VIP‐IR is most prominent in sacral afferent pathways. The distribution of VIP‐IR in spinal cord was very similar to the central projections of sacral visceral afferents. These findings are consistent with data from other experiments indicating that VIP may be a transmitter in visceral afferent pathways.
Cerebral cortical projections to the reticular regions around the trigeminal motor nucleus in the cat
Authors: Yasui Yukihiko , Itoh Kazuo , Mitani Akira , Takada Masahiko , Mizuno Noboru 
Published: May 2005

AbstractCerebral cortical regions which send projection fibers to the reticular regions around the trigeminal motor nucleus were identified in the cat by the horseradish peroxidase (HRP) method. The reticular region around the trigeminal motor nucleus are known to contain many interneurons for masticatory motoneurons. After injections of HRP into the reticular regions around the trigeminal motor nucleus, HRP‐labeled neuronal cell bodies in the cerebral cortex were found in layer V. They were distributed bilaterally in the orbitofrontal cortical regions, mainly in the rostral extension of the orbital gyrus close to the presylvian sulcus; more were located in the floor and lateral bank of the presylvian sulcus than in the crown of the orbital gyrus. After injections of HRP conjugated with wheat germ agglutinin (WGA‐HRP) into these cortical regions, many labeled presumed axon terminals were distributed bilaterally in the reticular regions around the trigeminal motor nucleus; mainly in the region ventral to the trigeminal motor nucleus and in the intertrigeminal region between the main sensory trigeminal nucleus and the trigeminal motor nucleus. Terminal labeling in these regions was more prominent after WGA‐HRP injection into the lateral bank of the presylvian sulcus than after WGA‐HRP injection into the crown of the orbital gyrus. Thus, the present results indicate that the main part of the cortical region projecting directly to the reticular regions around the trigeminal motor nucleus in the cat is folded into the presylvian sulcus.
Ontogeny of substance P‐like immunoreactive fibers in the taste buds and their surrounding epithelium of the circumvallate papillae of the rat. II. Electron microscopic analysis
Authors: Yamasaki Hiroshi , Tohyama Masaya 
Published: May 2005

AbstractWe studied the ontogeny of the fine structure of substance P‐like immunoreactive (SPI) fibers in the extragemmal epithelium and taste buds of the circurnvallate papillae in the rat tongue by electron microscopy and by the unlabeled antibody‐enzyme method. SPI fibers in the lamina propria first appeared at gestational day 19, and those in the extragemmal epithelium and in the taste buds at day 21. These fibers did not form synaptic contact with underlying cells. In addition, the occurrence of nonimmunoreactive fibers in these areas preceded that of SPI fibers. Our findings suggest that SPI fibers are not primarilly involved in the differentiation of the extragemmal epithelium and taste bud cells.