bluuebunny/crossref_metadata_2025_split huggingface dataset:
Postnatal development of interstitial (subplate) cells in the white matter of the temporal cortex of kittens: A correlated Golgi and electron microscopic study
Authors: Valverde F. , Facal‐Valverde M. V. 
Published: January 2005

AbstractThe early postnatal development of interstitial cells (IC) in the white matter of the temporal cortex in kittens was studied. Counts in Nissl‐stained preparations show that the number of 1C diminishes by about 60% during the second postnatal week. In Golgi preparations, IC are bipolar or bitufted with long, beaded dendrites coursing in the white matter toward the ventricular surface. Ascending, shorter dendrites are thinner, often branch in a short bush, and possess long spines resembling filopodia. The majority of their axons descend in the white matter, emitting numerous recurrent collaterals that become ascending fibers reaching various cortical layers. Most 1C resemble inverted pyramidal cells. They appear well developed at the time of birth and continue to develop elaborate axonal complexes in the white matter of older animals. Electron microscopic observations of degenerating 1C were detected in all cases studied and their presence was related to the existence of cell death responsible for elimination of a fraction of 1C. They were recognized by their dark aspect and by dilations of the endoplasmic reticulum. Synapses contacting degenerating profiles were also observed. It is concluded that 1C belong to the population of early generated subplate cells which may have a transient function involved in certain morphogenetic events during the development of the cortical plate. Some persist in the adult where they can be recognized as IC of the white matter.
Organization and synaptic relationships of the projection from the primary sensory to the primary motor cortex in the cat
Authors: Porter Linda L. , Sakamoto Kuniyo 
Published: January 2005

AbstractIt is known from previous studies that fibers originating from cells in area 2 of the cat primary somatosensory cortex project topographically to area 4 of the motor cortex and that they terminate preferentially in the caudal region of the cruciate sulcus. We examined this pathway to determine more precisely the distribution pattern of fibers and the laminar arrangement of axon terminals in the motor cortex. The recently developed technique of PHA‐L staining enabled us to label anterogradely the axons that form this projection. Iontophoretic injections of PHA‐L were made into the rostral bank of the ansate sulcus (area 2). After 7 days the cats were perfused and the tissue was processed immunohistochemically to stain the PHA‐L filled fibers. Light microscopic examination revealed that a small cluster of cells in the sensory cortex gave rise to multiple foci of labeled axons in area 4. The labeled fibers formed columnlike arrays, which were located for the most part in the posterior bank of the cruciate sulcus and were separated by irregular intervals of cortex devoid of labeled fibers. Clusters of labeled fibers were also found in the anterior region of the cruciate sulcus in some of the animals. The dimensions of the labeled areas and the small number of cells that gave rise to each group of fibers suggested that axonal branches of cells within the injection site formed the multiple foci. Variations in the immunohistochemical staining enabled us to study the laminar distribution of sensory cortex axon terminals with the electron microscope. Whereas some PHA‐L labeled terminals were found in the deep cortical layers, the majority (82%) were spread throughout layers I–III. Differences in the laminar distribution of sensory cortex afferents that formed axodendritic or axospinous synapses were noted. Synapses formed with dendritic shafts were relatively sparse (28%) and were confined to the superficial layers. Some of the more numerous axospinous synapses, which accounted for 72% of identified synapses, were found in layers V and VI, although most were in layers I–III. The distribution pattern of terminals showed little variation between columns in different areas of the motor cortex, including that in the anterior cruciate region. The pattern of termination of the sensory to motor cortex projection is discussed in relation to the physiological characteristics of this pathway.
Immunocytochemical and morphological evidence for a retinopetal projection in anuran amphibians
Authors: Uchiyama Hiroyuki , Reh Thomas A. , Stell William K. 
Published: January 2005

AbstractThe centrifugal projection to the retina in anuran amphibians (Rana catesbeiana and Xenopus laevis) has been investigated by immunocytochemistry, HRP transport, and optic nerve lesionings. FMRFamide‐ and N‐terminal substance P–immunoreactive (Fa‐ir and SP(3–7)‐ir) fibers were abundant in the normal retina and optic nerve but almost absent distal to an optic nerve section or crush after 7–14 days survival. Fa‐ir and SP(3–7)‐ir fibers were traced to the optic nerve from the lamina terminalis (or the septopreoptic junctional area), where there are many Fa‐ir and SP(3–7)‐ir perikarya. After application of HRP to the optic nerve and survival for 9–10 days, retrogradely labeled neurons were observed in the lamina terminalis. Conversely, following HRP injection into the septal and preoptic area, labeled fibers were observed in the optic nerve. These results suggest that Fa‐ir and SP(3–7)‐ir efferent fibers project from the lamina terminalis to the retina. But in anurans, unlike teleosts, these fibers are not gonadotropin‐releasing‐hormone (GnRH)‐ir. The morphological relations of this retinopetal pathway with the GnRH‐ir nervus terminalis are discussed.
Cingulate gyrus of the cat receives projection fibers from the thalamic region ventral to the ventral border of the ventrobasal complex
Authors: Yasui Yukihiko , Itoh Kazuo , Kamiya Hiroto , Ino Tadashi , Mizuno Noboru 
Published: January 2005

AbstractDirect projections to the cingulate gyrus from the thalamic region lying just ventrally to the ventral border of the ventrobasal complex (VB) were found in the cat by two sets of experiments that used WGA‐HRP (wheat germ agglutinin‐horseradish peroxidase conjugate).In the first set of experiments, WGA‐HRP was injected into the thalamic region around the ventral border of the VB. When the site of injection involved the thalamic region lying ventrally to the ventral border of the VB at the levels of the caudal two thirds of the VB. The cerebral cortex in the rostral part of the cingulate gyrus ipsilateral to the WGA‐HRP injection contained fine HRP‐positive granules, which indicated anterograde labeling of axon terminals. These labeled presumed axon terminals were mainly distributed to the superficial part of layer I, deep part of layer II, layer IV, and the most superficial part of layer V in the cingulate cortex.In the second set of experiments, WGA‐HRP was injected into the cerebral cortex of the rostral part of the cingulate gyrus. When the site of injection involved the region of the cingulate gyrus, where presumed axon terminals had been labeled in the first set of experiments, the thalamic region just ventral to the ventral margin of the caudal two‐thirds of the VB ipsilateral to the WGA‐HRP injection contained neuronal cell bodies labeled retrogradely.The results indicate that some neurons that are located in the thalamic region just ventral to the ventral border of the caudal two‐thirds of the VB send their axons to the cerebral cortex in the rostral part of the cingulate gyrus.The possible significance of the thalamocingulate projection found in the present study is discussed with relation to nociceptive behavior and function.
Somatostatin‐like immunoreactivity and glycine high‐affinity uptake colocalize to an interplexiform cell of the Xenopus laevis retina
Authors: Smiley John F. , Basinger Scott F. 
Published: January 2005

AbstractAntibodies directed against somatostain have been used to label a population of interplexiform cells (IPCs) in the Xenopus laevis retina. These cells have spherical soma which lie in the inner nuclear layer (INL), adjacent to or one cell distal to the inner plexiform layer (IPL). Processes from these cells project throughout the IPL, with a fairly dense accumulation of labeled dendrites in the upper two‐fifths of the IPL and a dense, narrow band of labeled dendrites adjacent to the ganglion cell layer. These cells also have finer processes, originating at the cell body, that traverse the INL and ramify in the outer plexiform layer (OPL). Double label experiments show that all of the cells that contain somatostatin‐like immunoreactivity (SOMLI) in the INL are also labeled by high‐affinity uptake with 3H‐glycine. Immunocytochemistry of retinal whole mounts shows that these cells are evenly distributed across the retina at a density of 542 ± 65 cells/mm2. On the basis of the colocalization experiments and the morphological homogeneity of these cells, we suggest that they represent a single cell type.Interplexiform cell processes were further characterized by electron microscopy after immunocytochemistry or 3H‐glycine autoradiography. In the IPL, IPC processes are seen to be postsynaptic at both ribbon and conventional synapses. This input is found almost entirely in the distal two‐fifths of the IPL. Interplexiform cell processes are presynaptic to unlabeled processes in both the distal and proximal IPL. In the OPL, labeled processes are found near or contiguous with photoreceptor bases, and are often presynaptic to small‐diameter processes. The postsynaptic processes have been identified as bipolar cell dendrites in six cases. Interplexiform cell processes may also contact horizontal cell processes in the OPL.
Lack of central sprouting of primary afferent fibers after ricin deafferentation
Authors: Pubols Lillian M. , Bowen David C. 
Published: January 2005

AbstractA new deafferentation technique, the application of ricin to peripheral nerves, was used to test for collateral sprouting of undamaged primary afferent fibers within the adult mammalian spinal cord dorsal horn. The right sciatic nerves in rats were injected with ricin 14 to 57 days prior to bilateral labelling of dorsal rootlets with horseradish peroxidase. To equate the number of surviving dorsal root fibers on the two sides, the left sciatic nerves were injected 5 days prior to labelling. In each animal, horseradish peroxidase was applied to a bilateral pair of lumbar or low thoracic dorsal rootlets 18 hours prior to sacrifice to test for sprouting by labelling primary afferent fibers and terminals in the right (experimental) and left (control) dorsal horns.Although there is overlap of degenerated and intact primary afferent fields in this preparation, a postulated precondition for sprouting (Murray and Goldberger: J. Neurosci. 6: 3205‐3217, '86), we found no evidence for sprouting of undamaged, myelinated afferent fibers in the experimental dorsal horns. The pattern of labelling was symmetrical in all animals, and the density of labelling was not consistently greater on the experimental side. These results support the conclusions of Rodin et al. (J. Comp. Neurol. 215: 187‐198, '83) and Rodin and Kruger (Somatosens. Res. 2: 171‐192, '84), who also found no sprouting in the rat's dorsal horn after surgical deafferentation, and do not support the assertion that the difference between the results of those studies and earlier studies in cats was due to a lack of overlap of degenerated and intact dorsal roots in the rat.
Neuroanatomical distribution of receptors for three potential inhibitory neurotransmitters in the brainstem auditory nuclei of the cat
Authors: Glendenning Karen K. , Baker Barbara N. 
Published: January 2005

AbstractIn order to visualize the relative abundance of each of three potentially inhibitory neurotransmitters in the nuclei of the brainstem auditory pathway, receptor sites for glycine, GABA‐A, and muscarinic acetylcholine (ACh) have been localized in the cat's brainstem auditory system. Conventional autoradiographic receptor‐binding procedures were used and the distributions of the receptors were inferred from the respective distributions of tritiated strychnine, muscimol, and quinuclidinyl benzilate (QNB) binding sites.The results show that glycine may be the major inhibitory neurotransmitter in the auditory system as it ascends to the midbrain in that relatively high levels of strychnine binding are present in every major nucleus of the system. In contrast, high levels of muscimol binding of high‐affinity GABA‐A receptors are confined mostly to the dorsal cochlear nucleus, the dorsal nucleus of the lateral lemniscus, and the central and cortical regions of the inferior colliculus, while high levels of QNB binding of muscarinic ACh receptors are seen only in the central and cortical regions of the inferior colliculus.
Immunocytochemical localization of luteinizing hormone‐releasing hormone (LHRH) in the brain and nervus terminalis of the adult and early neonatal gray short‐tailed opossum (Monodelphis domestica)
Authors: Fukuda Marlene Schwanzel , Fadem Barbara H. , Garcia Maria Soledad , Pfaff Donald W. 
Published: January 2005

AbstractLuteinizing hormone‐releasing hormone (LHRH) was detected by immunocytochemical procedures in cells and fibers in the brain and in the nervus terminalis of the adult and neonatal gray, short‐tailed opossum (Monodelphis domestica). As in several species of eutherian mammals, LHRH‐immunoreactive cells and fibers were seen in the medial septal nuclei, nucleus, and tract of the diagonal band and olfactory tubercle. Surprisingly, few LHRH‐immunoreactive cells were found in the hypothalamus or in the preoptic area in either the adult or neonate. LHRH‐immunoreactive fibers were seen in these regions and were numerous in the median eminence.The nervus terminalis in the gray opossum showed several distinctive characteristics. Immunoreactive and nonreactive cells, in ganglia along the fascicles of LHRH fibers and frequently lay adjacent to blood vessels. No LHRH‐immunoreactive branches of the nervus terminalis were found in contact with the vomeronasal nerves as they traversed the medial surfaces of the main olfactory bulbs en route to the accessory olfactory bulbs. The LHRH‐immunoreactive fibers in the central roots of the nervus terminalis formed a compact bundle on either side of midline, which coursed obliquely from clusters of ganglion cells on the ventromedial surface of the olfactory bulbs into the septum. Traced through serial sagittal sections, LHRH‐immunoreactive fibers, in continuity with those in the triangular nucleus of the septum, ran down and around the rostal face of the anterior commissure and fanned out into the medial preoptic area.As previously observed in the fetal guinea pig and rat, LHRH was detected in ganglion cells of the nervus terminalis of the newborn gray opossum preceding its detection in any other area of the brain.
Primary projections and efferent cells of the VIIIth cranial nerve in the monitor lizard, Varanus exanthematicus
Authors: Barbas‐Henry Heleen A. , Lohman Anthony H. M. 
Published: January 2005

AbstractIn order to describe the central relations of both the afferent and efferent components of the VIIIth cranial nerve in one reptile, the methods of anterograde and retrograde axonal transport and anterograde degeneration were used to study the vestibular and cochlear projections and the efferent system of this nerve in Varanus exanthematicus. On the basis of cresyl violet and Klüver‐Barrera staining, five vestibular nuclei, four cochlear nuclei, and two clusters of small cells which could not be designated as strictly auditory or vestibular are distinguished. The vestibular nuclei include the nucleus dorsolateralis, nucleus ventrolateralis, nucleus tangentialis, nucleus ventromedialis, and nucleus descendens. The well‐developed cochlear nuclear complex includes the nucleus angularis, nuclei magnocellulares medialis and lateralis, and nucleus laminaris. The two cell clusters are located dorsolaterally in the brainstem just ventrolateral to the acoustic tubercle.The primary afferent vestibular fibers coursing in the anterior VIIIth nerve root distribute to the ventral portions of all vestibular nuclei except nucleus ventromedialis, whereas the fibers coursing in the posterior root project to the dorsal portions of these nuclei. In nucleus ventromedialis fibers of both roots do not segregate into ventral and dorsal portions. Other targets of the vestibular fibers are the two cell clusters, the granular layer of the ipsilateral cerebellum, the reticular formation, and the descending trigeminal tract and its nucleus. The primary cochlear fibers coursing in the posterior root terminate in nucleus angularis, nuclei magnocellulares medialis and lateralis, and the inner cell strand of nucleus laminaris. The efferent system is, ipsi‐ and contralaterally in the brainstem, composed of ventral and dorsal cell groups that extend from the level of the principal abducens nucleus caudally where they overlap with the facial motor nucleus. The fibers, which originate from the contralaterally located efferent cells, course beneath the IVth ventricle to exit the brainstem on the ipsilateral side.
Basal forebrain efferents to the medial dorsal thalamic nucleus in the rhesus monkey
Authors: Hreib Kinan K. , Rosene Douglas L. , Moss Mark B. 
Published: January 2005

AbstractThalamic efferent connections of the basal forebrain (BF); medial septal nucleus (MS), vertical limb of the diagonal band (VDB), horizontal limb of the diagonal band (HDB), nucleus basalis (NB), and ventral pallidum (VP) were investigated in twelve rhesus monkeys. In five animals, injections of radioactively labeled amino acids were placed in the BF. In four animals, the injections involved different divisions of the NB, HDB, and the most ventral part of the VDB. In those four cases, labeled fibers in the medial forebrain bundle were observed traveling caudally towards the hypothalamus where some turned dorsally to enter the inferior thalamic peduncle. These fibers terminated in the ventral half of the magnocellular part of the medial dorsal thalamic nucleus (MDmc). In a fifth case, the amino acid injection involved most of the MS and the VDB. Labeled fibers traveled caudally from the injection site and entered the stria medullaris. These fibers then traveled caudally before turning ventrally to terminate in the dorsal half of MDmc. To determine which of the diverse neuronal types in the BF gives rise to these thalamic projections, in two monkeys injections of horseradish peroxidase (HRP) were placed into MDmc. Labeled neurons were observed throughout the full extent of the NB, the VDB, the MS, and part of the VP. In order to determine the extent of the cholinergic input to MDmc from the BF, one of the HRP cases was processed for the simultaneous visualization of HRP, and acetylcholinesterase (AChE), the hydrolytic enzyme for acetylcholine, and a second case was processed for simultaneous visualization of HRP, and choline acetyltransferase (ChAT), the synthetic enzyme for acetylcholine. We observed that 30–50% of the HRP‐labeled neurons were putatively cholinergic. In order to determine if the NB projection to MD is a collateral of the NB projection to orbital frontal cortex, one fluorescent retrograde tracer was injected into the orbital frontal cortex and one into MD. This case showed that approximately 5% of the BF neurons that project to MDmc also project to the orbital frontal cortex. These results confirm a significant subcortical projection by which the cholinergic system of the basal forebrain may influence higher cortical functions through the thalamus.
Regenerated optic fibers in goldfish reestablish a crude sectoral order in the visual pathway
Authors: Bernhardt Robert , Easter Stephen S. 
Published: January 2005

AbstractThe goldfish optic pathway is regenerated after an optic nerve crush. We have examined the axonal topography of the regenerated pathway by labeling, with horseradish peroxidase (HRP), axons originating from retinal sectors or annuli. The positions of the labeled axons in the cross section of the pathway were compared to the normal and related to the factors that may influence axonal pathfinding.The positions of retinal axons in the cross section of the normal pathway are predictable from the retinal addresses of the ganglion cells described by the polar coordinates r (the distance from the optic disc) and θ (the sectoral or clockface position). The two coordinates map orthogonally onto the cross section of the pathway; r varies monotonically along one axis; θ varies along a perpendicular axis.The normal r‐order, present in the nonregenerated stump of the experimental nerve, was severely degraded and perhaps lost entirely in the regenerated optic nerve, tract, and brachia. Sectoral order was also lost as the axons passed the crush site, but it was reestablished, albeit crudely, in the regenerated tract and brachia where axons tended to occupy positions appropriate to their dorsal, ventral, nasal, and temporal retinal origins. The exit sequence of the regenerated axons from the stratum opticum into the tectal neuropil was normal: temporal first, nasal last.These results suggest that the regenerating fibers followed some θ specific cue located in the nonaxonal environment. It seems likely that the original axons probably followed the same cue. In contrast, the absence of r‐order suggests that there is no r‐specific cue for the regenerates to follow. It seems likely that the original r‐order was a consequence of nonspecific influences—the orderly spatiotemporal growth of the retina and the existence of a permissive region for axonal growth.