bluuebunny/crossref_metadata_2025_split huggingface dataset:
The descending and intrinsic serotoninergic innervation of an elasmobranch spinal cord
Authors: Ritchie T. C. , Roos L. J. , Williams B. J. , Leonard R. B. 
Published: January 2005

AbstractThe descending and the intrinsic components of the Serotoninergic (5HT) innervation of the Atlantic stingray spinal cord were described by comparing the distributions of neuronal elements exhibiting 5HT‐like immunoreactivity (peroxidase‐antiperoxidase method) in sections caudal and rostral to spinal transections. The cells of origin of the descending 5HT system were located with a double labeling method for both retrogradely transported horseradish peroxidase (HRP) and 5HT staining.The descending system provides virtually the entire 5HT innervation of the dorsal horn, the intermediate zone, and the dorsal and lateral portions of the ventral horn. Fibers of the descending 5HT system course in the lateral funiculus, the dorsal portion of the ventral funiculus, and in the submeningeal zones of the dorsal and lateral aspects of the spinal cord. This projection primarily originates from the 5HT cell groups of the caudal rhombencephalon (groups II and III; Ritchie et al., '83), with a minor contribution from group IV in the rostral rhombencephalon. The organization of the descending 5HT system in stingrays is remarkably similar to that of mammals.The intrinsic spinal 5HT system consists of cells distributed in the ventromedial spinal cord that have processes extending longitudinally in a ventral submeningeal fiber network. Fibers were traced from the submeningeal system to the ventral horn, where varicose processes were restricted largely to the neuropil ventral to the somata of the fin motoneurons. The existence of a well‐defined intrinsic 5HT system in stingrays supports the hypothesis that such a system exists in the spinal cords of a variety of vertebrates.
Optic axons ignore denervated foreign territory in goldfish tectum
Authors: Marotte L. R. 
Published: January 2005

AbstractUltrastructural morphometry was used to test firstly, whether regenerating optic axons in goldfish tectum will form connections in adjacent denervated foreign territory and secondly, whether intact optic axons will collaterally sprout to innervate this territory. The stratum fibrosum marginale of the tectum was partially denervated by removing the torus longitudinalis and cutting the tectal commissure. Optic axons do not normally synapse in this layer. Thirty days after partial denervation and optic tract section the numbers of normal synapses in a μm2 column through the stratum fibrosum marginale reached a minimum and then started to increase so that by 159–173 days after the operation they had returned to control levels. Optic terminals, recognised by their degeneration after optic nerve section, did not contribute to these increasing numbers of synapses. Instead, optic axons preferentially reinnervated their normal tectal layers. Similarly, there was no evidence of collateral sprouting of intact optic axons into the partially denervated stratum fibrosum marginale and numbers of normal synapses in the layer also returned to control levels. These probably arose from collateral sprouting of terminals remaining after the partial denervation, raising the possibility that optic axons were prevented from synapsing there by the rapid occupation of vacant sites by other axons. However, delaying the partial denervation with respect to the tract section did not alter the result. These results support the idea of a specific affinity between optic axons and their postsynaptic targets.
Ultrastructure of the mouse leptomeninx
Authors: Oda Yoshio , Nakanishi Isao 
Published: January 2005

AbstractAn electron microscopic study was made of the mouse leptomeninx with special attention to the ultrastructure of the subarachnoid space. The arachnoid membrane was divided into outer and inner layers. The outer layer was composed of elongated cells in contact with one another with numerous tight junctions. The cells in the inner layer had intricate cytoprocesses, some of which embraced the connective tissue matrix containing collagen fibers. Beneath the arachnoid membrane, there were a loose meshwork of arachnoid cells and a single layer of pial cells. No arachnoid trabeculae were found. The intercellular space of the leptomeninx except in the outer layer of the arachnoid membrane was filled with Ruthenium Red‐positive flocculent material and particles, in which various amounts of the collagen fibers and microfibrils were embedded. Elastic fibers were not identified. The subarachnoid space, which is believed to be a specialized channel exclusively containing the cerebrospinal fluid, was not recognized. These observations indicate that the cerebrospinal fluid circulates through the broad intercellular space, which contains extracellular matrix, of the leptomeninx.
Distribution of local axon collaterals of mitral, displaced mitral, and tufted cells in the rabbit olfactory bulb
Authors: Kishi Kiyoshi , Mori Kensaku , Ojima Hisayuki 
Published: January 2005

AbstractTo determine the projection fields of intrabulbar axon collaterals, mitral, displaced mitral, and middle tufted cells in the rabbit olfactory bulb were stained by intracellular injection of HRP. The axon collaterals of mitral cells and displaced mitral cells were distributed exclusively within the granule cell layer (GrL). Those of middle tufted cells were distributed mostly in the GrL and on rare occasions in the mitral cell layer. None of these collaterals entered the external plexiform layer.Axon collaterals of mitral cells, emitted at the depths of the GrL, were distributed widely from the deep portion to the most superficial portion of the GrL. Collaterals of displaced mitral cells were also emitted in the deep part, but they tended to be distributed more superficially in the GrL than mitral cells. Collaterals of middle tufted cells were released and distributed superficially in the GrL.The axon collaterals of these principal cells typically extended for a longer distance than the secondary dendrites, and they sometimes formed bushlike terminal arborizations.The results indicate that the projection fields of the axon collaterals of principal cells are spatially separated from the dendritic projection fields. This suggests that the output of these principal cells through the collaterals has a functionally different role from the output through the dendrites. The observation that the three types of principal cells differ in the distribution pattern of their axon collaterals in the GrL suggests that there is a functional separation of the sublayers in the GrL.
Localization of forebrain neurons which project directly to the medulla and spinal cord of the rat by retrograde tracing with wheat germ agglutinin
Authors: Schwanzel‐Fukuda Marlene , Morrell Joan I. , Pfaff Donald W. 
Published: January 2005

AbstractWheat germ agglutinin (WGA) in a slow‐release polyacrylamide gel pellet was implanted in the medulla or spinal cord of the rat. Large numbers of retrogradely labeled cells were visualized by immunocytochemical procedures in specific nuclei of the forebrain mainly ipsilateral to the implant site following implants as far caudal as the sacral segments of the spinal cord. Total average number of labeled forebrain cells (three brains per category; 100 μm per 150 μm of brain tissue were examined microscopically): medulla, 2,115; cervical, 1,878; lumbar, 1,017; sacral, 385.After WGA‐gel implants in the medulla or cervical cord the majority of retrogradely labeled neurons were seen in the lateral hypothalamic area, the zona incerta, and in subdivisions, of the paraventricular nucleus. A continuum of labeled cells extended from the caudal part of the paraventricular nucleus into the posterior hypothalamus and into the central gray of the midbrain. Labeled cells were also seen in the medial basal hypothalamus and the rostral part of the bed nucleus of the stria terminalis. A few labeled cells were observed in the medial and lateral preoptic areas, the rostral part of the paraventricular nucleus, and in the arcuate nucleus.Following WGA‐gel implants in the lumbar or sacral cord many retrogradely labeled cells were observed mainly in the paraventricular nucleus, the lateral hypothalamus, zona incerta, medial basal hypothalamus, and posterior hypothalamic area. The continuum of labeled cells described above was also seen following these implants.Our data indicate that the lateral hypothalamus and zona incerta, as well as specific parts of the paraventricular nucleus, are major loci of neurons which project directly to the medulla and spinal cord of the rat. The consistency with which labeled cells were localized across all brains examined within categories of implant sites and the large numbers of labeled cells counted within these areas appeared to verify the sensitivity of our retrograde tracing method. Therefore, we interpret the paucity or absence of labeled cells in particular brain regions to indicate that cells of these regions do not project to the medulla or spinal cord.
Effects of permeability of midtectal barriers in goldfish on compression of the visuotectal projection rostrally and regenerative escape caudally
Authors: Edwards M. A. , Jacobson M. 
Published: January 2005

AbstractPhysiological mapping and anatomical methods were used to evaluate changes in the retinotectal projection of goldfish 16–200 days after insertion of permeable or impermeable barriers that bisected the tectum into rostral and caudal halves. The projection to rostral tectum was left intact. Barriers composed of Gelfilm or impermeable Nucleopore material induced within 2–3 months an orderly compression of the visual field representation in rostral tectum only slightly less complete than that observed in animals with caudal half‐tectal ablation. In contrast, Nucleopore filter barriers with 0.1‐μm or 8‐μm holes did not cause significant compression.According to both mapping and autoradiographic tracing, reinnervation of tectum behind the barriers occurred among all groups within 1–2 months. Physiologically, the projection caudal to permeable barriers was typically complete and appropriate, whereas the caudal projection in fish with impermeable barriers eventually consisted of a greatly expanded representation of the extreme temporal visual field. Autoradiography, normal fiber impregnations, and the orthograde horseradish peroxidase method revealed that regeneration past the barriers involved the formation of large bundles passing vertically along the cut Loctal margin and through the underlying valvula cerebelli or lateral tegmentum.The simultaneous rostral compression and caudal expansion in the visual representation formed when more impermeable barriers were used provides evidence that, in addition to the influence of position‐dependent properties, axonal competition for target territory contributes to the control of the distribution of optic arbors. Further research is required to determine why reinnervation of tectum caudal to the more permeable barriers was more complete with respect to visual representation.
Axonal projections of mechanosensory neurons in the connectives and peripheral nerves of the leech, Haemopis marmorata
Authors: Johansen Jørgen , Hockfield Susan , McKay Ronald D. G. 
Published: January 2005

AbstractThe axonal projections of the seven mechanosensory neurons in the connectives and peripheral nerves were examined by horseradish peroxidase (HRP) injections.In the connective the closely functionally related mechanosensory neurons travel in two bilaterally symmetrical regions, which comprise less than 10% of the connective's cross‐sectional area. This grouping may reflect the similar functional properties and synaptic connections of the cells.Serial sections through the neuropil‐connective junction zone showed that the organization of the axons is independent of glial fasciculation. Fascicles are not rigid structures; they were found to part and fuse in a seemingly random manner. The glial cell seems therefore to have only a supportive structural function and not to play any role in axonal guidance or to define any specific nerve fascicles in the leech.The projections of the mechanosensory cells in the peripheral roots were not as stereotyped as in the connective. However, examination of the branching of the medial and lateral P cells in the posterior root showed that the roots are highly structured and that some axons may be confined to tracts which have specific positions related to the branching of the root. The possible role of the P cells in pioneering these tracts is discussed.
The neural substrate for the pupillary light reflex in the pigeon (Columba livia)
Authors: Gamlin Paul D. R. , Reiner Anton , Erichsen Jonathan T. , Karten Harvey J. , Cohen David H. 
Published: January 2005

AbstractThe neural substrate of the pupillary light reflex in the pigeon was investigated using anatomical, stimulation, and lesion techniques. In birds, as in mammals, the sphincter pupillae muscle (which constricts the iris) is innervated by cells in the ciliary ganglion (Pilar and Tuttle, '82). These cells are in turn innervated by cells in the Edinger‐Westphal nucleus (EW) (Cowan and Wenger, '68; Narayanan and Narayanan, '76; Lyman and Mugnaini, '80). The efferent link of the pupillary light reflex must therefore involve cells in EW. To study the central course of this reflex pathway, injections of horseradish peroxidase (HRP) were placed in EW. These injections labeled cells in a number of regions including a contralateral pretectal nucleus, area pretectalis (AP). Only a limited number of cells in AP project to EW. Injections of tritiated amino acids into AP labeled a discrete region of the contralateral EW. This projection is confined to a dorsolateral region of caudal EW and overlies the somata of approximately 100 cells. Tritiated proline was injected into the eye, and the results confirmed an earlier report (Reperant, '73) that AP receives retinal input from the contralateral eye. Immunohistochemical studies demonstrated fibers in AP that stained positively for Substance‐P‐like, enkephalin‐like and tyrosine‐hydroxylase‐like immunoreactivity. Injections of HRP were placed in AP to examine the retinal ganglion cells mediating the reflex. Cells with an average diameter of approximately 14 μm (5–25 μm range) were labeled and averaged approximately 6 μm greater in diameter than the retinal ganglion cells (mean = 7.3 μm) labeled by an optic chiasm injection. The cells labeled by AP injections were distributed unevenly throughout the retina with a higher concentration in the central and temporal retina and a paucity in the red field and fovea. Our results demonstrate that AP receives input from a distinct sub‐population of large retinal ganglion cells that comprises a very small percentage of the total population of retinal ganglion cells. Unilateral lesions of AP abolished the pupillary light reflex in the eye contralateral to the lesion; stimulation of AP elicited pupilloconstriction in the eye contralateral to the stimulation site.These results delineate the central course of the pupillary light reflex pathway in the pigeon and identify the retinal ganglion cells that subserve this reflex. They show that, at every point in the pathway, only a few cells mediate this simple reflex. These studies have allowed us to compare the pupillary light reflex pathway in the pigeon and monkey, and based on recent anatomical studies in the monkey (Steiger and Buttner‐Ennever, '79; Magnuson et al., '80), we propose that the central course is similar in both species and that the projection from the pretectum to EW is entirely crossed.
Olivary projections from the mesodiencephalic structures in the cat studied by means of axonal transport of horseradish peroxidase and tritiated amino acids
Authors: Onodera Satoru 
Published: January 2005

AbstractBy means of horseradish peroxidase (HRP) and autoradiographic methods, olivary projections from mesodiencephalic structures were studied in the cat.Following HRP injections in various parts of the inferior olive, many cells were labeled ipsilaterally in the nucleus of Darkschewitsch, the nucleus accessorius medialis of Bechterew, the nucleus of the fields of Forel, and the subnucleus dorsomedialis and ventrolateralis of the parvocellular red nucleus. Some labeled cells also occurred ipsilaterally in the suprarubral reticular formation and a few labeled cells in the interstitial nucleus of Cajal.After injection of tritiated amino acids in different parts of the mesodiencephalic region mentioned above, labeled fibers were found in different parts of the inferior olive, presenting a high degree of the topographic correlation within the mesodiencephalo‐olivary projection, which was exclusively ipsilateral. That is, the nucleus of Darkschewitsch was found to project to the rostral half of the medial accessory olive and the dorsomedial cell column. There was mediolateral topographic relation in this projection. The nucleus accessorius medialis of Bechterew was found to project to the ventral lamella and the lateral part of the dorsal lamella as well as to a small rostromedial part of the caudal half of the medial accessory olive. The subnucleus dorsomedialis and ventrolateralis of the parvocellular red nucleus projected to the rostral and caudal halves, respectively, of the medial part of the dorsal lamella. The subnucleus ventrolateralis of the parvocellular red nucleus also sent fibers to the lateral part of the ventrolateral outgrowth. The nucleus of the fields of Forel, suprarubral reticular formation, and interstitial nucleus of Cajal appeared to project to the caudal half of the medial accessory olive, the medial part of the ventrolateral outgrowth, the rostral part of the dorsal cap, and the caudal part of the dorsal accessory olive.
Glycinergic neurons in the human retina
Authors: Frederick Jeanne M. , Rayborn Mary E. , Hollyfield Joe G. 
Published: January 2005

AbstractNeurotransmitter‐specific properties of glycinergic neurons in the human retina were studied using 11 pairs of eyes from donors ranging from 21/2 to 54 years in age. A mean endogenous level of 10.3 nmoles glycine per mg protein was measured by amino acid analysis in retinas isolated within 1 hour postmortem. When retinas were incubated with 3H‐glycine (2 μM) and processed for autoradiography, label was found associated with neurons whose somata reside within the inner nuclear layer. Some heavily labeled neurons located at the vitread border of the inner nuclear layer were identified as amacrine cells based on ultrastructural verification of the conventional synaptic contacts made by their processes in distal regions of the inner plexiform layer. In proximal regions of the inner plexiform layer, dendrites of glycine‐accumulating amacrine cells were postsynaptic to both ribbon and conventional synaptic contacts, suggesting input from bipolar and other, nonglycinergic amacrine cells. Their density (30 ± 11 S.D. cells/mm linear retinal expanse) tended to be greater toward the central fundus. A second population of lightly labeled, probable bipolar cells was present in the middle of the inner nuclear layer; the density of this second set of glycine‐accumulating cells approximated that of the heavily labeled population from the fovea, centrally, to the ora serrata, peripherally. Release of either accumulated or endogenous glycine was elicited by K+‐depolarization in a Ca2+‐dependent manner. Tissue fragments exposed for 6 minutes to normal medium, 40 mM K+‐substituted medium, or K+‐substituted medium with Co2+ release endogenous glycine into each bathing solution in average amounts of 0.6, 2.6, and 0.7 nmoles per mg protein, respectively. Together these data strongly implicate glycine as a neurotransmitter in the human retina.
Distribution and projections of cholecystokinin‐immunoreactive neurons in the hypothalamic paraventricular nucleus of rat
Authors: Kiss J. Z. , Williams T. H. , Palkovits M. 
Published: January 2005

AbstractAnalysis of coronal sections from colchicine‐treated rat brains reveals that CCK‐immunoreactivity (CCK‐ir) is present in two distinguishable neuronal systems in the paraventricular nucleus (PVN). More than 60% of these cells were found to be typical parvicellular neurons; the remainder were magnocellular neurons. The magnocellular CCK‐ir neurons were concentrated in the medial magnocellular subdivision, while more caudally they formed a ring around a zone of unstained magnocellular neurons. Immunostained parvicellular neurons predominate in medial and periventricular parvicellular subdivisions.The efferent projections of CCK‐ir neurons were investigated by looking for retrograde accumulation of CCK‐ir in cell bodies after selective knife cuts. A parasagittal cut of the lateral retrochiasmatic area as well as transection of the rostral median eminence resulted in an accumulation of CCK‐ir material in a large number of both parvi‐ and magnocellular neurons. After pituitary stalk lesions, however, increased staining was only seen in magnocellular neurons. It is inferred that the magnocellular (presumed oxytocin‐CCK) cells send their axons to the pituitary, whereas axons of CCK‐ir parvicellular neurons appear to terminate in the median eminence.After transection of the medial forebrain bundle (MFB), immunostaining increased in a small number of scattered transected fibers proximal to the knife cut and in a few perikarya in the PVN, indicating that very few CCK cells may send descending fibers to the lower brainstem.
A Golgi analysis of the primate globus pallidus. I. Inconstant processes of large neurons, other neuronal types, and afferent axons
Authors: François Chantal , Percheron Gérard , Yelnik Jérôme , Heyner Simone 
Published: January 2005

AbstractThe present paper is a Golgi study, with high‐power lenses, of the primate globus pallidus. Two kinds of inconstant processes of large neurons are first described: complex endings and thin processes. Complex endings are thick apparatuses terminally located on dendrites having many appendages of various types. Contacts were observed not only between striatal axons and these complex endings but also between complex endings and the soma, dendritic stems, dendritic portions or complex endings of other large pallidal neurons. Thin processes were usually beaded, very thin, and arose from any part of the dendritic tree. Contacts were seen between them and soma or dendrites of other large neurons. These thin processes were very similar to initial axonal collaterals and together constitute a common pool of processes. Complex endings and thin processes were essentially observed in the lateral nucleus of the pallidum where they apparently are evenly distributed inside the nucleus but randomly distributed on individual neurons. Two neuronal types other than large pallidal neurons were isolated: the smallest were considered to be local circuit neurons, while intermediate‐sized neurons might be the origin of a particular efference. Many striatal axons gave no branches over long distances and collaterals were of two types and most frequently were short (less than 50 μm). Larger axonal arborizations were rarely encountered. In addition to parallel contacts, numerous very short ones were observed. All these contacts between striatal axons and dendrites of large pallidal neurons seem to be irregularly distributed.