bluuebunny/crossref_metadata_2025_split huggingface dataset:
The distribution of hypothalamic and extrahypothalamic vasotocinergic cells and fibers in the brain of a lizard, Gekko gecko: Presence of a sex difference
Authors: Stoll C. J. , Voorn P. 
Published: May 2005

AbstractThe distribution of vasotocin in the brain of the lizard Gekko gecko was studied with immunocytochemical methods. Vasotocinergic cells were found in the nucleus supraopticus, the nucleus paraventricularis, the bed nucleus of the stria terminalis, and in the rhombencephalon. Vasotocinergic fibers were found in the preoptic area, the lateral and ventral hypothalamus, and in many extrahypothalamic brain areas.Furthermore, evidence was obtained of a conspicuous sex difference with regard to vasotocinergic innervation of the lateral septum, the ventrocaudal telencephalon (nucleus sphericus), and the periaqueductal gray; in these areas vastocinergic innervation is much denser in males than in females.The results are discussed in relation to the sexually dimorphic vasopressinergic innervation of the rat brain. It is suggested that the vasotocinergic fiber system in the sexually dimorphic brain areas in Gekko gecko is related to the bed nucleus of the stria terminalis.
Development of the spinal‐medullary projection from the mouse barrel field
Authors: Crandall James E. , Whitcomb Julie M. , Caviness Verne S. 
Published: May 2005

AbstractNeurons in layer V of the murine posteromedial barrel subfield (PMBSF) project to structures at or caudal to the spinal‐medullary junction. During postnatal development a reduction occurs in the density of the neurons which form this projection. In principle, three processes might be expected to contribute to this reduction: cell death, tissue growth, and axon pruning. Three different paradigms in which cells of origin of the projection are labeled retrogradely with True Blue, injected into the spinal‐medullary junction, taken together with an estimate of the relative growth of layer V, provide separate estimates of the magnitude and rate of reduction consequent to these different processes during the first 3 postnatal weeks. The density of neurons in an index sector of layer V of the PMBSF which contribute to the projection at varied ages is estimated by injections made at a range of ages from postnatal day 1 (P1) to P16, with a survival of 4 days in each instance. Overall reduction in density is 80%. The component due primarily to axon pruning is estimated to be 50% by injections delivered at graded ages from P1 to P16 with survival to P20 in each instance. The component of the reduction attributable to increase in volume is estimated at 30% by a series of injections delivered at P1 with graded survival times from P5 through P20. A reduction due to cell death is not identified. The reduction in density due to tissue growth is essentially linear through the interval P5–P11. At all ages, neuronal somata of origin of the spinal‐medullary projection are located within layer V. Subsequent to P15 they are confined to sublayer Vb; at earlier ages somata in Va and Vc also contribute axons to the projection. Although volume increase due to growth of the neuropil reduces the density of the population contributing to the projection equally in all three sublayers, final elimination of all contributions from Va and Vc depends upon axon pruning.
Spinal projections to the lateral reticular nucleus in the rat: A retrograde labelling study using horseradish peroxidase
Authors: Shokunbi M. T. , Hrycyshyn A. W. , Flumerfelt B. A. 
Published: May 2005

AbstractThe organization of the spinal projection to the lateral reticular nucleus (LRN) in the rat was investigated by means of a retrograde pathway tracing method in which horseradish peroxidase (HRP) served as an enzyme marker. Discrete placements of HRP into the LRN were achieved by a combination of dorsal (stereotaxic) and ventral (microsurgical) approaches. The extent and distribution of retrogradely labelled neurons in the spinal cord indicated a substantial and highly ordered projection to the LRN. All segments of the spinal cord contributed to the projection to the LRN. The limb enlargements were the richest sources of projection. The projection from the cervical spinal cord was bilateral with ipsilateral preponderance. The cervical neurons projecting to the ipsilateral LRN were located mainly in lamina VII of the spinal cord, while those projecting to the contralateral LRN were located mainly in lamina VIII. The lumbar spinal projection terminated in the contralateral LRN, and the neurons of the origin were located mainly in lamina VIII.Most if not all parts of the LRN received afferents from the spinal cord. The projections terminated most abundantly in the caudomedial portions of the magnocellular LRN. The medial aspect of the LRN was the site of preferential termination of the cervical spinal projection. Lumbar spinal projections terminated preferentially in the rostrolateral region of the nucleus. These two imputs overlap in the central region of the nucleus.
Cholinergic innervation of the rat hippocampus as revealed by choline acetyltransferase immunocytochemistry: A combined light and electron microscopic study
Authors: Frotscher Michael , Léránth Csaba 
Published: May 2005

AbstractThe cholinergic innervation of the rat hippocampus proper and fascia dentata was investigated by using a monoclonal antibody against choline acetyltransferase (ChAT). At the light microscopic level, thin varicose ChAT‐immunoreactive fibers were observed mainly in the vicinity of the pyramidal and granular layers where they formed a fine network around proximal dendrites of pyramidal and granule cells. In addition, many ChAT‐immunoreactive fibers were found in the hilar region and in stratum oriens, radiatum, and lacunosum‐moleculare of all hippocampal sectors.Electron microscopic analysis revealed ChAT immunoreactivity in thin unmyelinated varicose axons and terminals which established synaptic contacts. Asymmetric contacts of ChAT‐immunoreactive terminals were found on small spines in the dendritic layers of the hippocampus proper and in the molecular layer of the fascia dentata. Symmetric synaptic contacts were formed on the cell bodies of pyramidal and granule cells. Both symmetric and asymmetric synaptic contacts occurred on dendritic shafts. The analysis of serial thin sections, which allows identification of postsynaptic elements, suggests that pyramidal cells, granule cells, and nonpyramidal neurons of the hippocampus receive a cholinergic input.
Axonal projections from transplanted ectopic legs in an insect
Authors: Sivasubramanian P. , Nässel D. R. 
Published: May 2005

AbstractEctopic legs were produced in the fleshfly Sarcophaga bullata by transplantation of leg imaginal discs. Cobalt or horseradish peroxidase (HRP) fills from these supernumerary legs showed that their sensory axons invariably innervate the metathoracic leg neuropil via an abdominal nerve. This was so irrespective of whether they differentiated from pro‐, meso‐, or metathoracic leg disc. Implantation of left leg discs on the right side and vice versa revealed that the site of implantation determined which side (left or right) of the ganglion was innervated. In general, the same results were obtained when the implantation was made after removal of a leg disc from the host, except in a few instances in which the implanted leg directly innervated the deafferented leg neuropil. The results indicate that axonal pathfinding from the imaginal discs in this insect is via contact guidance along preexisting nerves or imaginal disc stalks.
Observations on the somatodendritic morphology and axonal trajectory of intracellularly HRP‐Labeled efferent neurons located in the deeper layers of the superior colliculus of the cat
Authors: Moschovakis A. K. , Karabelas A. B. 
Published: May 2005

AbstractEfferent neurons of the deeper layers of the cat's superior colliculus were stained with horseradish peroxidase (HRP) to demonstrate patterns of somatodendritic morphology and axonal trajectory. A combination of somatodendritic and axonal features of the HRP‐labeled cells revealed the existence of three major groups of tectal efferent neurons (X, T, and I). X neurons are mostly large and multipolar and participate in the crossed descending and ipsilateral ventral ascending projections of the superior colliculus. The X group includes multipolar radiating (X1), tufted (X2), large vertical (X3), medium‐sized vertical (X4), and medium‐sized horizontal (X5) neurons. T neurons participate in one or two of the major tectofugal bundles (medial descending ipsilateral, lateral descending ipsilateral, medial dorsal ascending, crossed descending) besides providing a commissural branch. They also issue recurrent collaterals distributed within a more or less restricted area of the deeper layers. The T group includes medium‐sized, trapezoid, radiating (T1) and small or mediumsized, ovoid, vertical (T2) neurons. I neurons participate in the ipsilateral descending projection of the superior colliculus. They are small, triangular or ovoid, sparsely ramified cells that provide long, varicose collaterals irregularly distributed within the deeper layers. The majority of T neurons are located in the ventral stratum opticum or dorsal stratum griseum intermedialem, X3 and X5 neurons are situated immediately below in the dorsal stratum griseum intermediale, while X1, X2, X4, and I neurons are indiscriminately distributed within the deeper layers. The polythetic classification presented here provides a conceptual framework for the description of tectal efferent neurons. It is open‐ended and can thereby accomodate new cells types as indicated by the disclosure of a small horizontal (A) and a small radiating (unclassified) neuron. Moreover, it does not preclude the construction of alternate taxonomies. A dendro‐architectonic classification into four groups [vertical (X3, X4, T2, I), horizontal (X5, A), radiating (X1, T1, I), and tufted (X2)] can be made and would relate to the mode of integration of various tectopetal inputs. A classification based on the dorsoventral location of tectal efferent neurons is also possible and would relate to the dorsoventral distribution of neurons with specific response properties.
Distribution of cholecystokinin‐like immunoreactivity in the rat main olfactory bulb
Authors: Seroogy Kim B. , Brecha Nicholas , Gall Christine 
Published: May 2005

AbstractThe anatomical localization of cholecystokinin‐like immunoreactivity (CCK‐I) within the rat main olfactory bulb was analyzed by using the‐peroxidase‐antiperoxidase immunocytochemical technique. Neurons or neuronal processes containing CCK‐I were localized within all laminae of the olfactory bulb except the olfactory nerve fiber layer. A large population of CCK‐I neurons, with morphology, size, and distribution corresponding to that of the middle and external tufted cells, was observed within a zone extending from the deep periglomerular region through the superficial one‐half to one‐third of the external plexiform layer. A smaller number of immunoreactive perikarya were found in the deep external plexiform layer, the glomerular layer, and rarely within the inner plexiform layer. These CCK‐I neurons appeared to correspond to internal tufted cells, periglomerular cells, and deep short‐axon cells, respectively. Dense CCK‐I staining of fibers and terminals was present within the internal plexiform layer and, less densely, within the neuropil of the granule cell layer. In addition, terminal‐like CCK‐I was localized within layer 1A of the anterior olfactory nucleus, the olfactory tubercle, and the most rostral piriform cortex. This observation provides corroboration for the identification of the principal CCK‐I neuron in the rat olfactory bulb as the centrally projecting middle tufted cell. The present results, demonstrating the localization of CCK‐I to both local circuit and projection neurons of the olfactory bulb and to terminal‐like puncta in the internal plexiform and granule cell layers, suggest that CCK may be significantly involved in olfactory processing at several levels.
A callosal projection of area 17 upon the border region of area MT in the marmoset monkey, Callithrix jacchus
Authors: Kunz Birgit , Spatz W. B. 
Published: May 2005

AbstractInjections of the retrograde tracer HRP into the border region of the temporal visual area MT and adjoining cortex in Callithrix labeled pyramidal neurons in area 17 of the contralateral hemisphere. Evidence is presented that this newly discovered heterotopic callosal projection of the monkey striate cortex connects regions of representation of the zero vertical meridian of the visual field in a retinotopic order.
The development of acetylcholinesterase activity in normal and transplanted superior colliculus in rats
Authors: Harvey A. R. , MacDonald A. M. 
Published: May 2005

AbstractHistochemical techniques have been used to examine the development of the enzyme acetylcholinesterase (AChE) in normal and transplanted rat superior colliculus (SC). At birth (P0), relatively little AChE activity was found in SC in situ; however, there was a gradual increase in the intensity of AChE staining in the SC over the first 4 postnatal weeks. In the superficial layers, an increase in AChE activity was first seen in rostromedial SC at P6 and was found throughout the upper tectal layers by P10. An increase in AChE activity in the intermediate layers was apparent by P12 and the adult pattern, characterized by periodic bands of AChE staining, was established by P22.In tectal grafts, the development of AChE activity followed a time course similar to that found in normal SC. Mature tectal grafts contained moderate AChE activity with AChE‐positive cells scattered throughout the neuropil. There were however, localized, often spherically shaped areas which displayed relatively intense AChE activity. These AChE‐dense areas had a characteristic appearance in adjacent sections stained for Nissl or neurofibrils. Significantly, host retinal input, where present, was always restricted to the AChE‐dense regions and it seems certain that these areas are homologous to the superficial layers of normal SC. AChE‐rich regions were also present, however, in grafts which received no retinal input and in general the pattern of AChE activity in tectal grafts was strikingly similar, irrespective of their location or connections with the host brain. It would appear, therefore, that much of the AChE activity in tectal transplants, and presumably in SC in situ, is intrinsic to that region and not derived from or dependent upon extrinsic innervation.
Spinal and trigeminal dorsal horn projections to the parabrachial nucleus in the rat
Authors: Cechetto David F. , Standaert David G. , Saper Clifford B. 
Published: May 2005

AbstractWe studied afferents to the parabrachial nucleus (PB) from the spinal cord and the spinal trigeminal nucleus pars caudalis (SNVc) in the rat by using the anterograde and retrograde transport of wheat germ agglutinin conjugated to horseradish peroxidase (WGA‐HRP). Injections of WGA‐HRP into medial PB retrogradely labeled neurons in the promontorium and in lamina I of the dorsal rostral SNVc, while injections into lateral PB and the Kölliker‐Fuse nucleus retrogradely labeled neurons in these areas as well as in lamina I throughout the caudal SNVc and spinal dorsal horn. Injections of WGA‐HRP into the caudal SNVc and dorsal horn of the spinal cord resulted in terminal labeling in the dorsal, central, and external lateral subnuclei of PB and the Kölliker‐Fuse nucleus, all of which are known to receive cardiovascular and respiratory afferent information. Injections of WGA‐HRP into the promontorium and dorsal rostral SNVc resulted in terminal labeling in the same PB subnuclei, as well as in the medial and the ventral lateral PB subnuclei, which are sites of relay for gustatory information ascending from the medulla to the forebrain. The spinal and trigeminal projection to PB may mediate the convergence of pain, chemosensory, and temperature sensibilities with gustatory and cardiorespiratory systems in PB.
Topographic organization of facial motoneurons to individual pinna muscles in rat (Rattus rattus) and bat (Rousettus aegyptiacus)
Authors: Friauf Eckhard , Herbert Horst 
Published: May 2005

AbstractThe location and number of motoneurons to individual pinna muscles were determined by retrograde transport of horseradish peroxidase in rat and flying fox. The degree of ear mobility differs considerably between these species in that rats perform simpler ear movements while flying foxes move their pinnae in a sophisticated way. Five pinna muscles were investigated in each species. Motoneurons lay within the medial subdivision of the facial motor nucleus extending over its entire rostrocaudal length. They were topographically organized; however, a somatotopic order could not be observed. With one exception homologous pinna muscles were represented in corresponding areas in both species, supporting the idea of a common representation of ear muscles in mammals. In rat, motoneuron pools overlapped considerably, whereas in flying fox overlap was minute. A total of 1,110 and 1,646 motoneurons were labeled in rat and flying fox, respectively. We conclude that the higher number of pinna motoneurons in the latter species in addition to the more clear‐cut topography provide the structural substrates that underlie differences in the quality of ear movements as seen in bats vis‐a‐vis other mammals.
Primary sensory ganglion cells projecting to the principal trigeminal nucleus in the mallard, Anas platyrhynchos
Authors: Kishida Reiji , Dubbeldam Jacob L. , Goris Richard C. 
Published: May 2005

AbstractThe trigeminal and glossopharyngeal ganglia of the adult mallard were studied following HRP injections into the principal trigeminal nucleus (PrV). The PrV consists of the principal trigeminal nucleus proper (prV) and the principal glossopharyngeal nucleus (prIX). After an injection into the prV, the labeled cells were found in the ipsilateral trigeminal ganglion. After an injection into the prIX, labeled cells were found in the ipsilateral distal glossopharyngeal ganglion, but not in the proximal ganglion of the IX and X cranial nerve (pGIX + X).In Nissl preparations, two types of ganglion cells in the trigeminal ganglion, pGIX + X, and distal ganglion of N IX could be distinguished: larger light cells and smaller dark cells. We could not determine whether the HRP‐labeled cells belonged to both types or to one of them; but because all the labeled cells were over 20 μm, we concluded that the smallest cells (10–19 μm) in the trigeminal ganglion and distal ganglion of N IX did not project to the PrV.The labeling of the cells in the distal ganglion of N IX (average 34.5 μm) was uniformly moderate. In the trigeminal ganglion there were two types of labeled cells: heavily labeled cells (average 29.1 μm) and moderately labeled cells (average 35.1 μm). These two types of labeling (moderate and heavy) may reflect two types of primary sensory neurons: cells with ascending, nonbifurcating axons, and cells with bifurcating axons. We speculate that the former are proprioceptive neurons and the latter tactile neurons. Labeled bifurcating axons in the sensory trigeminal complex gave off collaterals to all parts of the descending trigeminal nucleus except to the caudalmost laminated spinal part.
Sensorimotor cortical projections to the primate cuneate nucleus
Authors: Cheema S. , Rustioni A. , Whitsel B. L. 
Published: May 2005

AbstractThe organization of the corticocuneate pathway was investigated in monkeys by using the anterograde and retrograde axonal transport of either horseradish peroxidase (HRP) or wheat germ agglutinin conjugated to horseradish peroxidase (WGA‐HRP).Injection of either tracer into the precentral cortex (centered on area 4) results in heavy anterograde labeling in the tegmental region, which lies immediately ventrolateral to the cuneate nucleus, particularly at levels caudal to the obex. On the other hand, injections of the same tracers involving areas 3b, 1, and 2 cause anterograde labeling mainly within the core (pars rotunda of Ferraro and Barrera, '35, Arch. Neurol. Psychol. 33:262–75) of the cuneate nucleus. Anterograde labeling is also evident in the rostral parts of the cuneate nucleus, especially after injections involving areas 1 and 2. Injections restricted largely to area 3b cause anterograde labeling preferentially in the core of the cuneate nucleus.After injection of HRP or WGA‐HRP into the dorsal medulla, retrogradely labeled neurons are present both in the pre‐ and postcentral gyrus, but their location depends upon the sites and extent of the injection site. When the tracer diffuses into the underlying tegmental area, many retrogradely labeled neurons appear in the precentral motor cortex, principally in area 4 although some of them also occur in area 6. With smaller injections, largely restricted within the cuneate nucleus, most labeled neurons are present in the postcentral gyrus, with the largest population in areas 1 and 2; a smaller number of small neurons in area 3b are best demonstrated with WGA‐HRP; and area 3a contains the smallest complement of retrogradely labeled neurons.The data from these studies suggest a segregation of pre‐ and postcentral afferents in the ventral tegmental region and the cuneate nucleus, respectively. These findings pertaining to the corticocuneate projection in the monkey are discussed in relation to (1) the parallelism between monkeys and cats (2) possible physiological implications of the anatomical organization described, and (3) conflicting evidence in the neurophysiological observations obtained, by earlier investigators, by antidromic and orthodromic activation of this pathway.
An ultrastructural study of cat lumbosacral γ‐motoneurons after retrograde labelling with horseradish peroxidase
Authors: Lagerbäck Per‐Åke 
Published: May 2005

AbstractTwelve retrogradely horseradish peroxidase (HRP)‐labelled triceps surae motoneurons of gamma size (mean cell body diameter<38 μm) were studied ultrastructurally. The contours of the cell bodies, as observed in the transverse midnucleolus plane, were elongated to rounded. The axons identified all originated from the cell body. The mean diameter of the stem dendrites was 4.5 μm.A substantial part of the cell membrane was covered by glial extensions. The boutons and synaptic contacts apposing the γ‐motoneurons could be classified into two categories on the basis of the the type of synaptic vesicles: S‐type boutons with spherical synaptic vesicles and F‐type boutons with flattened vesicles. In each neuron, the values for mean length and mean area of apposition, percentage synaptic covering, and packing density of S‐type, F‐type, and S + F‐type boutons were estimated on the cell body and in two dendritic compartments. In comparison with α‐motoneurons and Renshaw cells, the cell bodies of the γ‐motoneurons were covered by smaller and strikingly fewer boutons of both the S‐ and F‐types. The values for percentage synaptic covering and packing density of boutons on the proximal dendrites were also lower for γ‐motoneurons than for both α‐motoneurons and Renshaw cells, although the differences were less pronounced than on the cell body. No boutons of the C‐, M‐, and T‐types described for α‐motoneurons were found on the γ‐motoneurons.