bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dendritic organization of the human spinal cord: The motoneurons
Authors: Schoenen J. 
Published: December 2004

AbstractThe dendritic organization of motoneurons was analyzed with the Golgi stain and a morphometric method in the immature and adult human spinal cord. Each motoneuronal column was found to be characterized by a specific orientation of dendritic trees and by a distinct pattern of dendritic bundling.Ventromedial motoneurons have a pyramidal dendritic tree with numerous, short longitudinal branches and elongated dorsal branches. The latter form thick bundles oriented toward the ventral gray commissure. Longitudinal dendrites form a narrow‐meshed dendritic plexus, containing abundant microbundles. Motoneurons of the ventromedial column have fewer primary dendrites and a lower ramification index than other motoneurons. Central motoneurons are predominantly oriented longitudinally. The meshes of the rostrocaudal dendritic plexus are looser and the microbundles are finer. Most transverse dendrites run laterally and participate in dendritic bundles which penetrate into the ventrolateral funiculus. The rostrocaudal dendritic domain of ventrolateral motoneurons is the largest dendritic domain of all spinal neurons. The longitudinal dendritic network contains fine microbundles and appears wide‐meshed. Transverse dendrites form lateral or media dendritic bundles depending upon the position of their perikaryon. Dorsolateral motoneurons differ from other motoneurons by their multipolar organization with a slight preponderance of dorsoventral dendritic spread. Rudimentary lateral dendrite bundles are restricted to marginal neurons.The longitudinal plexuses of motoneuronal dendrites and the verticotrans verse dendrite bundles of the ventromedial column are well developed in the 26–28‐week‐old fetus. In contrast, the horizontotransverse dendrite bundles of central and ventrolateral motoneurons can only be recognized from 36 weeks on.The possible specific functions of the various types of dendrites bundles are examined and a laminar dendroarchitectonic schema of the human cord is proposed.
Brainstem projections of sensory and motor components of the vagus nerve in the rat
Authors: Kalia Madhu , Sullivan J. Michael 
Published: December 2004

AbstractThe sensory and motor connections of the cervical vagus nerves and of its inferior ganglion (nodose ganglion) have been traced in the medulla and upper cervical spinal cord of 16 male Wistar rats by using horseradish peroxidase (HRP) neurohistochemistry. The use of tetramethyl benzidine (TMB) as the substrate for HRP permitted the visualization of transganglionic and retrograde transport in sensory nerve terminals and perikarya, respectively. The vagus nerve in the rat enters the medulla in numerous fascicles with points of entry covering the entire lateral aspect of the medulla extending from level +4 to ‐ 6 mm rostrocaudal to the obex. Fascicles of vagal sensory fibers enter the dorsolateral aspect of the medulla and travel to the tractus solitarius (TS) which was labeled for over 8.8 mm in the medulla. The caudal extent of the TS receiving vagal projections was found in lamina V of the cervical spinal cord (C1 to C2). Sensory terminal fields could be visualized bilaterally in the nucleus of the tractus solitarius (nTS), area postrema (ap) and dorsal motor nucleus of the vagus nerve (dmnX). The ipsilateral projection to the nTS and the dmnX was heavier than that found on the contralateral side. The area postrema was intensely labeled on both sides. Motor fibers from HRP‐labeled perikarya in the dmnX travel ventromedially in a distinct fascicle and subsequently subdivide into a number of small fiber bundles that traverse the medullary reticular formation in the form of a fine network of HRP‐labeled fibers. As these fibers from the dmnX approach the ventrolateral aspect of the medulla they are joined by axons from the nucleus ambiguus (nA), nucleus retroambigualis (nRA) and the retro facial nucleus (nRF). These latter fibers form hairpin loops in the middle of the reticular formation to accompany the axons from the dmnX exiting from the medulla in a ventrolateral location. HRP‐labeled perikarya, in contrast to transganglionically transported HRP in sensory terminals in the nTS, were visualized on one side only, thus indicating that motor control via the vagus nerve is exerted only by motor neurons located ipsilaterally. Sensory information on the other hand, diverges to many nuclear subgroups located on both sides of the medulla.
An intracellular HRP study of the rat globus pallidus. I. Responses and light microscopic analysis
Authors: Park M. R. , Falls W. M. , Kitai S. T. 
Published: December 2004

AbstractA study of the intracellularly recorded responses of rat globus pallidus neurons to activation of striopallidal fibers was combined with light microscopic examination of the morphology of these same neurons using intracellular horseradish peroxidase.The response to stimulation of caudate‐putamen is an inhibitory post‐synaptic potential with observed latencies ranging from 5.1 to 9.8 msec. These values correspond to conduction velocities of 0.4 to 0.8 m/second for striopallidal fibers. Comparison with extracellular controls shows no excitatory component to the response.All recovered and analyzed neurons (n = 11) were of the large type of pallidal neuron known from Golgi studies but with the addition that two subtypes could be recognized. Large neurons located medially in the nucleus had dendritic fields with large dorsoventral extent (ca. 1 mm) when compared to their mediolateral and rostrocaudal dimensions (ca. 0.4 mm) and these neurons emitted no axon collaterals. Large neurons located laterally in the nucleus had disklike dendritic fields with both dorsoventral and rostrocaudal dimensions being on the order of 1 mm but with a minor axis of approximately 100 μm. The axons of these neurons possessed collaterals. As a consequence of their disk‐shaped dendritic field, neurons belonging to the laterally placed subgroup and occupying the narrow (ca. 100 μm thick) striopallidal border zone known to receive a distinct input from neostriatum have dendrites restricted to that zone.
Laminar organization of peptide‐like immunoreactivity in the anuran optictectum
Authors: Kuljis Rodrigo O. , Karten Harvey J. 
Published: December 2004

AbstractPeptide‐ 5‐hydroxytryptamine (5‐HT)‐, tyrosine hydroxylase (TOH)‐, and glial fibrillary acidic protein (GFAP)‐like immunoreactivity was studied in the optic tectum of Rana pipiens. Peroxidase‐antiperoxidase and indirect immunofluorescence single‐ and double‐labeling methods were used to compare differential laminar distribution of each of these substances.Substance P (SP), leucine‐enkephalin (LENK), cholecystokinin octapeptide (CCK8), bombesin (BOM), avian pancreatic polypeptide (APP), and possibly neurotensin display unique individual patterns of laminar distribution of processes and cell bodies throughout the tectum. A correlative analysis of the topographical distribution of SP, LENK, BOM, and APP on the basis of double‐labeled sections shows a pretise laminar segregation of these substances. Vasoactive intestinal peptide‐, β‐endorphin‐, and rana‐tensinlike immunoreactivity is consistently absent from our material. 5HT‐and TOH‐like immunoreactivity discloses a reticular array of fibers without clear evidence of laminar organization. This peptide‐like laminar organization is particularly elaborate throughout the superficial neuropil of the optic tectum, the major retinorecipient zone. The pattern of lamination demonstrated in the present study differs in several important features from that previously described on the basis of several histological methods.The cells of origin of processes(axons and/or dendrites) in the superficial tectal neuropil may be either intrinsic or extrinsic to the tectum. Special reference is made to conflicting evidence regarding the possibility of a recinal contribution to peptide‐like tectal lamination.
The development of pyramidal neurons after eye opening in the visual cortex of hooded rats: A quantitative study
Authors: Juraska Janice M. 
Published: December 2004

AbstractDendritic maturation of pyramidal neurons in layers III and V of the rat visual cortex was quantified in rapid Golgi‐stained tissue from socially housed hooded rats at ages 15, 30, and 60 days. A complex pattern of changes emerged. Dendritic branching analyses revealed that in layer III both bifurcating and terminal basilar branches increased in length over the sampled days. Likewise, total dendritic length increased in the layer III basilar dendritic tree between 15 and 30 days of age and peaked at 30 days of age in the layer III apical oblique branches. No changes in dendritic length were observed in layer V pyramidal neurons. Neither layer III nor layer V neurons exhibited any changes in the number of basilar or apical oblique branches over the time period studied.Dendritic spine density increased on terminal basilar branches in both cell populations between 15 and 30 days. There also was an increase in spine density on the layer V pyramidal apical shaft between 15 and 30 days, while on layer III bifurcating basilar branches, spine density fell between 30 and 60 days. These data indicate that while dendrites may continue to grow longer, pyramidal neurons do not on average generate additional branches after day 15. However, the pattern of spine density is still changing between 15 and 60 days of age. Thus no single developmental pattern holds for all cell populations or even across areas of the dendritic field within a population.
Distribution and structural characterization of neurons giving rise to descending spinal projections in the turtle, Pseudemys scripta elegans
Authors: Woodson W. , Künzle H. 
Published: December 2004

AbstractDescending spinal projections were investigated in the turtle Pseudemys scripta elegans following injections of horseradish peroxidase and/or radioactive wheat germ agglutinin into the spinal cord at various levels. Using various planes of section the cells of origin in the brainstem, cerebellum, and diencephalon were characterized according to their size, dendritic tree, and precise location.Projections to levels as far caudal as the lumbar spinal cord were found to arise from medial and lateral rhombencephalic reticular fields, including the perihypoglossal complex, the nucleus raphe inferior, and the locus coeruleus; from certain subdivisions of the vestibular complex (ipsi‐lateral subnucleus (subn.) ventrolateralis, contralateral subn. veritrome‐dialis, and possibly subn. tangentialis); from the motor trigeminal nucleus; from the contralateral red nucleus, the ipsilateral nucleus (n.) interstitialis of the fasciculus longitudinalis medialis (flm) and from the hypothalamus. Fibers to high cervical levels arose from neurons within the dorsolateral and superior vestibular nuclei, the lateral cerebellar nucleus, the mesen‐cephalic trigeminal nucleus, and from neurons of the optic tectum. Low cervical and thoracic spinal levels were reached by fibers from the torus semicircularis n. laminaris, the n. of the flm, the medial cerebellar nucleus as well as from the n. vestibularis inferior and the principal and descending trigeminal nuclei.
Corticothalamic projections from postcruciate area 4 in the dog
Authors: Tanaka Duke , Sakai Sharleen T. , Görska Teresa 
Published: December 2004

AbstractCorticothalamic projections from postcruciate area 4, located on the rostral part of the posterior sigmoid gyms, were traced with the autora‐diographic technique in the dog. Injections of tritiated amino acids were made into the lateral and medial parts of area 4 in regions corresponding to the forelimb and hindlimb areas of the primary motor cortex, respectively. In cases with injections placed in the lateral part of areas, dense accu‐mulations of label were present in the lateral part of the ventral anterior nucleus (VA), the central part of the ventral lateral nucleus (VL), the ventral half of the ventral posterior inferior nucleus (VPI), the caudal part of the central lateral nucleus (CL), and the centrum medianum (CM). Lighter label was also present in the lateral part of the cytoarchitectonically distinct VL region bordering the ventrobasal complex (VB), as well as in the ventro‐lateral part of the mediodorsal nucleus (MD), and in the lateral posterior nucleus (LP). In one case in which the injection site involved an adjacent part of area 3a, label was also seen ventrally in the medial division of the posterior nuclear group (POm). However, no detectable differences in VL, MD, or intralaminar labeling patterns were noted between this case and the four other cases with injections confined to the lateral part of area 4. In two cases with injections restricted to the medial part of area 4, dense label was present in the lateralmost part of VL, the ventral part of VPI, the caudal part of CL, and CM. Lighter label was also present in the VL region bordering the dorsolateral edge of VB and in LP. An additional case in which the injection also involved the rostral border of area 3a showed a similar pattern cf thalamic labeling. Projections from both the lateral and medial parts of area 4 were also noted in the subthalamic nucleus, zona incerta, and nucleus of Darkschewitsch.These results suggest that Corticothalamic projections from postcruciate area 4 to VL are organized topographically such that projections from the lateral part of area 4 project centrally within VL while those from the medial part of area 4 project more laterally. Both parts of area 4 also project top‐ographically to a cytoarchitectonically distinct region of VL located im‐mediately adjacent to VB, In contrast, the projections to the intralaminar nuclei do not appear to be topographically organized. The data from cases involving spread of the injection into area 3a suggest that projection pat‐terns from area 3a to ventral, intralaminar, and medial thalamic nuclei are similar to those from area 4. However, it appears that at least the lateral part of area 3a also projects to POm.
The cell bodies of origin of sympathetic and sensory axons in some skin and muscle nerves of the cat hindlimb
Authors: McLachlan Elspeth M. , Jänig W. 
Published: December 2004

AbstractCell bodies of sensory and sympathetic axons projecting to skin and skeletal muscle of the cat hindlimb have been labeled retrogradely with horseradish peroxidase (HRP) in order to study location, size, and numbers of the somata of these neurons. HRP was applied to the freshly transected axons of nerves supplying hairy skin (superficial peroneal, SP; sural, Su), hairy and hairless skin of the paw (medial plantar, MP), or skeletal muscle (gastrocnemius‐soleus, GS). Serial sections of lumbosacral dorsal root and sympathetic ganglia were studied after standard histochemical processing. Additionally, the numbers of myelinated fibers in the same nerves were determined.All sensory somata and 99.4% of sympathetic cell bodies were located ipsilaterally. Sensory somata were commonly restricted to two adjacent dorsal root ganglia (usually L6–7 for SP, MP; L7‐S1 for Su, GS). Although sympathetic somata were more widely distributed rostrocaudally, their maximum frequency always occurred in the segmental ganglia immediately rostral to the sensory outflows, i.e., corresponding to rami communicantes grisei.Dimensions of sympathetic somata varied little between populations projecting to different tissues and were unimodally distributed. The size distributions of sensory somata were characterized by a peak between 10 and 20 μm radius, similar to sympathetic somata, and a varying smaller number of cells ranging up to 60 μm radius. Each nerve had a characteristic distribution profile of afferent somata. A population of very small cells was only present in GS, while the largest sensory somata in GS and MP were bigger than those in SP and Su.Numerical analysis of the data disclosed the characteristic composition of both myelinated and unmyelinated fibers in each nerve studied.
The morphology, ultrastructure, and distribution of synapses on an intersegmental interneurone of the locust
Authors: Watson A. H. D. , Burrows M. 
Published: December 2004

AbstractThe structure and synaptic relationships of an intersegmental inter‐neurone in the mesothoracic ganglion of the locust were studied by intra‐ccllular labelling for light and electron microscopy. Before labelling, the interneurone was characterized physiologically. It is depolarized and pro‐duces spikes when either of the two forewings are elevated, and by sensory inputs from the tarsi of the middle legs. The gross morphology of the in‐terneurone is quite distinctive. Its cell body is on the ventral surface of the ganglion near the midline and its primary neurite lies in the T‐tract. Its axon performs a characteristic lateral loop around the lateral dorsal tract before entering an anterior connective and ascending at least as far as the prothoracic ganglion. Within the mesothoracic ganglion, the interneurone gives rise to a profusion of branches. Ultrastructural examination and re‐construction of three regions of the interneurone from serial sections shows that input and output synapses are present in approximately equal num‐bers, and often are close to each other. There is no evidence for separate input and output regions. Output synapses are characterized by the presence of a presynaptic bar and a population 500‐2,000 round, electron‐lucent vesicles. Most of the estimated 105‐10 6 synapses occur on the smaller di ameter processes or on spines. The spines are of uniform diameter along their lengths, and are pre‐ or postsynaptic or both, but the postsynaptic spines are of smaller diameter than the others.
A quantitative electron microscope study of the perikaryal projections of sensory ganglion neurons. I. Cat and rabbit
Authors: Pannese Ennio , Gioia Magda , Carandente Orazio , Ventura Raoul 
Published: December 2004

AbstractWith a quantitative method and serial sections a study was carried out under the electron microscope of the perikaryal projections of the neurons in the thoracic spinal ganglia of cat and rabbit. These projections usually appear as finger‐shaped evaginations which run roughly parallel to the surface of the nerve cell body. Their length ranges between 0.3 and 3.25 μm, and they show a nearly circular cross section with a rather uniform transverse diameter having an average value of about 0.2 μm.Both in cat and rabbit 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. Perikaryal projections increase the surface area of the nerve cell body by 43% in cat and 39.5% in rabbit.These findings support the idea that perikaryal projections in sensory ganglion neurons are normal formations, which maintain the surface‐to‐volume ratio above the critical level for metabolic exchanges.
Reorganization in granuloprival cerebellar cultures after transplantation of granule cells and glia. I. Light microscopic and electrophysiological studies
Authors: Seil Fredrick J. , Leiman Arnold L. , Blank Nathan K. 
Published: December 2004

AbstractGranuloprival cerebellar cultures were transplanted after 9 or 16 days in vitro with cerebellar explants that had been exposed to kainic acid. The latter contained granule cells and differentiated glia, elements lacking in granuloprival cultures. Changes induced by transplantation observed by light microscopy included interposition of granule cells among the large cortical neurons of host explants; a reduction of the excess neurites of the Purkinje cell axon collateral system that is characteristic of granuloprival explants; and the appearance of myelinated fibers in previously unmyeli‐nated cultures. The most notable electrophysiologic consequence of transplantation was the disappearance of inhibition of cortical spontaneous activity in response to antidromic stimulation of Purkinje cell axons, correlating with the disappearance of excess neurites, and suggesting that Purkinje cell recurrent collateral inhibition was no longer the dominant mode of cortical inhibition. Restoration of missing elements in granuloprival cultures incited development of structural and functional characteristics resembling those of normal cerebellar explants.
Connections of the bullfrog striatum: Afferent organization
Authors: Wilczynski Walter , Northcutt R. Glenn 
Published: December 2004

AbstractAfferents to the dorsal and ventral striatum of the bullfrog (Rana catesbeiana) were revealed by horseradish peroxidase (HRP) histochemistry. Anterograde tracing techniques (autoradiography and anterograde HRP transport) were then used to confirm the projections and to describe their terminal fields within the striatum. The major input arises from the ipsi‐lateral lateral anterior and central thalamic nuclei, which receive tectal (Rubinson, ′68) and toral (Neary, ′74) input, respectively. These projections terminate in a dense, homogeneous field within the striatal neuropil adjacent to the cell plates of both striatal divisions. A second heavy input arises from the anterior entopeduncular nucleus bilaterally, with axons from the contralateral side crossing in the anterior commissure. This input terminates in both striatal divisions but is heaviest ventrally, Sparser inputs are present from the ipsilateral lateral and medial amygdalar nuclei, the preoptic area (mainly from the very caudal suprachiasmatic division), the posterior tuberculum, and the ipsilateral superficial isthmal reticular nucleus of the tegmentum. All these afferents, with the possible exception of the preoptic input, ascend to the striatum via the lateral forebrain bundle, and all innervate both striatal divisions. The preoptic input terminates within the cell plates, as well as subpially in a pattern similar to that described for tubercular input (Neary and Wilczynski, ′77). The tegmental input is very sparse and is most apparent superficially. Afferents from pallial telencephalic areas are not present, suggesting that although an‐urans receive striatal input from the diencephalon and mesencephalon, they do not possess a homolog of the mammalian corticostriatal system. Further, the extremely heavy input from the middle dorsal thalamic zone suggests that a major function of the anuran striatum involves processing sensory information from the midbrain roof.