bluuebunny/crossref_metadata_2025_split huggingface dataset:
Distribution of cerebellothalamic neurons projecting to the ventral nuclei of the thalamus: An HRP study in the cat
Authors: Nakano Katsuma , Takimoto Tamotsu , Kayahara Tetsuo , Takeuchi Yoshiki , Kobayashi Yoshitaka 
Published: December 2004

AbstractDistribution of cerebellothalamic neurons projecting to the ventral nuclei of the thalamus was examined in the cat, using the horseradish peroxidase (HRP) method.After injections of HRP within the lateral or ventrolateral portions of the ventroanterior and ventrolateral nuclear complex of the thalamus (VA‐VL), neurons labeled retrogradely with HRP were seen contralaterally in the cerebellar nuclei; many of them were situated in the nucleus interpositus anterior and nucleus interpositus posterior, and a moderate number of them were located in the nucleus lateralis. Labeled neurons in the nucleus interpositus posterior were observed mainly in the medial and ventral portions of the nucleus. On the side ipsilateral to the injections, a few labeled neurons were seen in the nucleus interpositus anterior, nucleus interpositus posterior, and nucleus lateralis. Virtually no labeled neurons were found in the nucleus medialis of the cerebellum.After HRP injections into the medial or dorsomedial portions of the VA‐VL, many labeled neurons were found contralaterally in the ventral and ventrolateral portions of the nucleus interpositus posterior, as well as in the nucleus lateralis, especially in its ventral and lateral portions. On the side ipsilateral to the injections, labeled neurons in the nucleus lateralis and nucleus interpositus posterior were small in number. In the nucleus medialis only a few labeled neurons were found bilaterally in the caudal levels of the nucleus.After HRP injections centered on the ventromedial nucleus of the thalamus, many labeled neurons occurred bilaterally in the caudal portions of the nucleus medialis, with a slight contralateral preponderance, and contralaterally in the lateral and ventral portions of the nucleus lateralis. A few labeled neurons were also seen contralaterally in the ventrolateral and lateral portions of the nucleus interpositus posterior, and ipsilaterally in the nucleus lateralis.
Early prenatal development of substance P and enkephalin‐containing neurons in the rat
Authors: Pickel Virginia M. , Sumal Khushdev K. , Miller Richard J. 
Published: December 2004

AbstractThe peroxidase‐antiperoxidase (PAP) technique is used to determine the time of first detection and distribution of neuronal perikarya and processes showing substance P (SP)‐ and enkephalin (EN)‐like immunoreactivity (LI) in the central and peripheral nervous system of the fetal rat. SPLI is first detected in central perikarya at E15. By E18, SPLI is less intensely localized in certain nuclei and shows heavier accumulations of immunoreactivity in central processes in peripheral sensory neurons. ENLI is also widely distributed in perikarya and processes of the central nervous system at E18, but is not detected at E15. The distribution of SPLI and ENLI at E18 is comparable to that previously described in the adult brain with the following exceptions: (1) labeled perikarya and processes are not detected in the rostral forebrain; (2) axonal pathways are intensely labeled whereas most terminal fields are devoid of immunoreactivity.
An analysis of the axon populations in the nerves to the pelvic viscera in the rat
Authors: Hulsebosch Claire E. , Coggeshall Richard E. 
Published: December 2004

AbstractThe present study uses selective surgical ablations combined with electron microscopic analyses to determine the number of axons in yarious catagories in rat hypogastric, pelvic, and pudendal nerves, these being the nerves to the pelvic viscera in this animal. Unmyelinated fibers predominate in all of these nerves. One of the most significant findings is that the pelvic nerve contains almost as many postganglionic sympathetic fibers as the hypogastric nerve. Previous investigators thought that the pelvic nerve supplied the parasympathetic inflow and the hypogastric nerve the sympathetic inflow to the pelvic viscera. The finding that there is a sizable sympathetic component in the pelvic nerve negates this idea, at least for the rat, and presumably calls for a reevaluation of the syndromes that arise from pelvic as opposed to hypogastric nerve section. Other findings of interest are (1) that there are unmyelinated efferent axons in the pudendal nerve, indicating that the pudendal is not a typical somatic nerve, (2) that the hypogastric nerve has a very small sensory component, and (3) that there are fibers surviving in the distal stumps of all these nerves, particularly the pelvic and hypogastric nerves.
The ascending input to the midbrain periaqueductal gray of the primate
Authors: Mantyh Patrick W. 
Published: December 2004

AbstractTo obtain a comprehensive map of the brainstem and spinal cord areas that project to the mesencephalic central gray small injections of hors‐radish peroxidase were made into various regions of the periaqueductal gray in a series of monkeys.Despite the fact that different regions of the central gray were injected in separate animals, the majority of the brainstem areas containing retrogradely filled neurons remained the same. Labeled neurons were observed in the superior colliculus, periaqueductal gray, lateral parabrachial, locus coeruleus, nucleus raphe magnus and pallidus, and a variety of brainstem reticular nuclei.In contrast to labeled brainstem areas, where labeled neurons were present predominantly ipsilateral to the injection site, the spinal trigeminal nucleus pars caudalis and the spinal cord displayed labeled cells chiefly on the side contralateral to the injection. Also in contrast to the labeled brainstem sites, where medial and lateral injection sites produced a similar pattern of labeling, medial injections in the PAG labeled almost exclusively neurons in the deep laminae (V‐X) in the spinal trigeminal nucleus pars caudalis and spinal cord while more lateral injections labeled neurons in both the deep (V‐X) and superficial (I) laminae. No consistent differences were noted in the location of labeled neurons in either brainstem or spinal sites after dorsal vs. ventral injections or caudal vs. rostral injection sites.The present study has demonstrated that the central gray receives afferent projections from a number of brainstem and spinal areas which are known to be involved in the modulation andor conduction of nociception, while other inputs are probably involved in the regulation of visceral functions. These data support the hypothesis that the mesencephalic periaqueductal gray functions as a visceral, nociceptive, and cognitive integrator.
A light and electron microscopic study of regrowing pyramidal tract fibers
Authors: Kalil Katherine , Reh Thomas 
Published: December 2004

AbstractAutoradiographic and EM techniques were used to study the regenerative capacity of severed axons in the mammalian CNS. In infant and adult hamsters the pyramidal tract was severed unilaterally in the medulla several millimeters rostral to the decussation. After, survival to adulthood, the animals received injections of [3H] Proline in the sensorimotor cortex ipsilateral to the lesion. Autoradiography showed that labeled pyramidal tract axons in the medulla did not cross the lesion site. Instead, in animals with infant lesions there was massive new axonal growth arising from the severed pyramidal tract several millimeters rostral to the cut. Most of these labeled fibers crossed to the contralateral brainstem, coalesced into a compact bundle, descended just medial to the spinal trigeminal nucleus, and grew caudally for 6–7 mm. Although the trajectory of the regrowing axons was completely abnormal, their pattern of termination in the dorsal column nuclei and dorsal horn of the cervical spinal cord was normal. Synapse formation by the anomalous regrowing pyramidal tract axons in their appropriate terminal areas was confirmed by electron microscopy of terminal degeneration in animals with infant pyramidotomies followed by adult cortical lesions. Autoradiographic labeling of the new pathway at short post‐lesion survival timers showed that the fibers grew out rapidly at about 1 mm/day, a rate somewhat slower than normal (2–4 mm/day).There was a dramatic difference in the capacity of the pyramidal axons to regrow in animals operated as infants vs. those operated as adults. The regrowth was maximal in animals with lesions at 4–8 days of age. Capacity for new growth declined sharply thereafter such that after 20 days of age, pyramidal tract lesions elicited no new growth but instead a progressive axon degeneration retrograde to the lesion.These results, in contrast to many previous findings, show that significant regrowth of severed axons can occur in the neonatal CNS. Most importantly pyramidal tract fibers regrowing by anomalous routes can nevertheless establish synaptic connections in appropriate terminal areas and thus, as we show in the following paper, play a functional role in maintaining normal motor behavior.
Afferent and efferent connections of the striate and extrastriate visual cortex of the normal and reeler mouse
Authors: Simmons Peter A. , Lemmon Vance , Pearlman Alan L. 
Published: December 2004

AbstractIn order to analyze the role of lamination in establishing the precisely ordered connectional pattern of the neocortex, we compared the afferent and efferent connections of the visual cortical areas in normal mice with those of the mutant mouse reeler (rl). The reeler mutation causes disruption of the laminar organization of the neocortex; all classes of neurons are present but are abnormally located. The corticocortical and thalamocortical connections of visual cortical areas 17, 18a, and 18b were determined in normal and reeler mice with injections of horseradish peroxidase (HRP) or HRP conjugated with wheat germ agglutinin (HRP‐WGA). The diffusion of HRP‐WGA is highly restricted due to the surface binding properties of the lectin; it was particularly effective in demonstrating retinotopically ordered connections.We found that the patterns of connections made by the reeler mutant are indistinguishable from normal. Cortical loci in area 17 are reciprocally connected to homotopic locations in areas 18a and 18b. Area 17 is also reciprocally connected with the dorsal lateral geniculate nucleus of the thalamus and projects to the superior colliculus. Areas 18a and 18b are reciprocally connected with each other and with the lateral posterior and lateral nuclei of the thalamus, respectively. In addition, we found evidence of reciprocal connections between the lateral posterior nucleus and area 17, and between the lateral nucleus and areas 17 and 18a.The results indicate that neurons in visual cortical areas of the reeler mutant mouse are capable of forming retinotopically organized corticocortical and thalamocortical connections in a pattern similar to that found in normal animals. Thus the genetic anomaly producing incorrect neuronal positioning during development of the reeler cortex does not seriously impede the pathway and target recognition mechanisms responsible for formation of functionally appropriate cortical connections.
The luteinizing hormone‐releasing hormone pathways in rhesus (Macaca mulatta) and pigtailed (Macaca nemestrina) monkeys: New observations on thick, unembedded sections
Authors: Silverman A. J. , Antunes J. L. , Abrams G. M. , Nilaver G. , Thau R. , Robinson J. A. , Ferin M. , Krey L. C. 
Published: December 2004

AbstractImmunocytochemical procedures on thick, unembedded tissue sections were used to study the localization of LHRH neurons and fibers in the diencephalon and mesencephalon of rhesus and pigtailed macaques. Cell bodies were visualized in large numbers. Much of their dendritic arborization was also filled with reaction product. Cell bodies were present in the preoptic area, the periventricular hypothalamic zone from the level of the anterior hypothalamus to the premammillary nuclei, the infundibular nucleus, supraoptic nucleus, several septal nuclei, the nervus terminalis, and the amygdala. The localization of LHRH cells in several of these areas represents new observations. LHRH axons were observed to innervate the portal vessels in the median eminence, the organum vasculosum of the lamina terminalis, the medial mammillary nuclei, the epithalamus, and the amygdala. These observations are discussed in relationship to the regulation of gonadotropin secretion in the primate.
Insula of the old world monkey. II: Afferent cortical input and comments on the claustrum
Authors: Mufson Elliott J. , Mesulam M.‐Marsel 
Published: December 2004

AbstractThe afferent connections of the insula in the rhesus monkey were studied with axonal transport methods. Injections of horseradish peroxidase (HRP) in the insula revealed labeled neurons in the prefrontal cortex, the lateral orbital region, the frontopariefal operculum, the cingulate gyrus and adjacent medial cortex, the prepiriforrn olfactory cortex, the temporal pole, the cortex of the superior temporal sulcus, the rhinal cortex, the supratem‐poral plane, and the posterior parietal lobe.Tritiated amino acid (TAA) injections in some of the cortical regions which contained retrogradely labeled neurons confirmed projections to the insula from prefrontal granular cortex, orbital frontal cortex, prepiriform cortex, temporal pole, rhinal cortex, cingulate gyrus, frontal operculum, and parietal cortex.In these studies, cortical areas that projected to the insula also projected to the claustrum. However, the topographic and quantitative relationships between the projections into the insula and those into the claustrum were inconsistent. Moreover, the claustrum has additional connections which it does not share with the insula. A selected review of the literature suggests that the claustrum and insula differ widely also with respect to ontogenesis and functional specialization.
Stability of neuron number in cortical barrels of aging mice
Authors: Curcio C. A. , Coleman P. D. 
Published: December 2004

AbstractThe question of whether age‐related neuron loss occurs in the cerebral cortex of rodents, as it apparently does in humans, has not been directly answered by previous studies. The barrel, a discrete morphological and functional unit in rodent somatosensory cortex, is a favorable system in which to address the problem of neuron loss during senescence. The numerical density and absolute number of neurons as well as barrel volume were determined from a computer‐assisted three‐dimensional reconstruction of thick (100 μm) and semithin (1 μm) sections through a single barrel, C3, from inbred mice (C57Bl/6NNia) at 4, 12, 22, 26, 30, and 33 months of age.The number and density of neuron and glial cells and the volume of the barrel did not change significantly with age. These data indicate that neuron loss is not a universal phenomenon in senescence and that there may be significant species differences in the aging of laboratory rodents and humans.
The cell masses in the brainstem of the South African clawed frog Xenopus laevis: A topographical and topological analysis
Authors: Nikundiwe Alfeo M. , Nieuwenhuys Rudolf 
Published: December 2004

AbstractThe ventricular sulcal pattern and the cytoarchitecture of the brainstem of Xenopus laevis, a pipid frog which retains a lateral line system throughout life, were studied in transverse Nissl‐ and Klüver‐Barrera‐stained serial sections. Four distinct longitudinal sulci, the sulcus medianus inferior, the sulcus intermedius ventralis, the sulcus limitans, and the sulcus medianus superior, could be distinguished. With the aid of the usual cytoarchitectonic criteria 42 cell groups were delineated; seven of these are primary efferent or motor nuclei, 13 are primary efferent or sensory centers, seven nuclei are considered to be components of the reticular formation, and the remaining 15 cell masses can be indicated as “relay” nuclei. In order to provide a basis for experimental work, the topographical position of the nuclei is illustrated in photomicrographs of representative levels and in graphical reconstructions.The distribution of the cell masses and their relations to the ventricular sulci were studied with the aid of the reconstruction procedure termed topological analysis (cf. Nieuwenhuys, '74; Fig. 19). This analysis yielded the following results. The sulcus limitans extends throughout almost the entire brainstem, dividing this part of the brain into a motor basal plate and a sensory alar plate. The cell masses in the rhombencephalic basal plate fit into two longitudinal zones, a medial area ventralis and a lateral area intermedioventralis. The former contains somatomotor centers of primary and higher order, whereas the latter is composed of three primary visceromotor nuclei and one visceromotor coordinating center. The rhombencephalic alar plate is occupied by viscerosensory, general somatosensory, and special somatosensory cell masses. Two centers, the nucleus fasciculi solitarii and the nucleus visceralis secundarius, represent together a discontinuous viscerosensory zone, which is situated immediately dorsal to the sulcus limitans. The general somatosensory nuclei, i.e., the gracile and cuneate nuclei, the nucleus tractus descendens of V, and the nucleus princeps of V constitute a zone which largely overlaps the viscerosensory zone. The special somatosensory area, i.e., the area of termination of (1) primary vestibular, (2) primary acoustic, and (3) lateral line nerve fibers, is strongly developed and occupies a considerable part of the alar plate. Presumably, the fibers of each of the three categories mentioned terminate in three separate zones of gray. The midbrain can also be subdivided bilaterally into a basal plate and an alar plate. The former occupies the medial part of the tegmentum mesencephali and may be considered as the rostral extreme of the somatomotor zone. The latter comprises the lateral tegmentum and the tectum, areas which are chiefly occupied by special somatosensory (visual, acoustic, lateral line) centers.
Nuclear organization of the bullfrog diencephalon
Authors: Neary Timothy J. , Northcutt R. Glenn 
Published: December 2004

AbstractA cytoarchitectonic analysis was performed on the diencephalic nuclei of the bullfrog, Rana catesbeiana. The epithalamus contains two widely recognized habenular nuclei. The thalamus has three subdivisions: dorsal and ventral thalamus, and posterior tuberculum. The dorsal thalamus may be further parcelled into anterior, middle, and posterior zones. Connectional data from other studies support this zonation. The anterior zone projects to the telencephalic pallium. The middle zone nuclei receive a strong input from the midbrain roof and project to the telencephalic striatal complex. The posterior zone nuclei do not appear to project to the telencephalon; they may eventually be placed in the pretectum, a transitional area between the diencephalon and mesencephalon. Two of the ventral thalamic populations have been frequently placed in the dorsal thalamus and called the nucleus rotundus and the lateral geniculate nucleus. These terms imply homology with sauropsid dorsal thalamic nuclei, but our analysis and current connectional information do not support such homologies. We have given these populations more neutral names. The hypothalamus is divisible into a preoptic and infundibular hypothalamus, and the preoptic area can be further separated into anterior and posterior preoptic areas. The posterior area contains the magnocellular preoptic nucleus and a dorsal arm of this nucleus, often placed in the ventral thalamus, was recognized. We have tentatively placed the posterior entopeduncular nucleus in the hypothalamus.
Organization of the afferent projections to the Wulst in the pigeon
Authors: Bagnoli Paola , Burkhalter Andreas 
Published: December 2004

AbstractThe afferent connections to the Wulst, a well‐defined bulge in the fore‐brain roof, were studied in the pigeon. Cells of origin were identified by horseradish peroxidase retrograde tracing, after placing multiple injections in the Wulst.The results demonstrate a bilateral intratelencephalic pathway arising from the archistriatum intermedium (Ai) in the basal forebrain. Labeled cells in n. superficialparvocellularis (SPC) and n. dorsolateralis posterior (DLP) on both sides of the brain, provide anatomical evidence for a bilateral forebrain projection of the somatosensory thalamus. A sparse ipsilateral input of unknown function from the medial thalamus originates in n. dor‐somedialisanterior(DMA)and n. dorsolateralis medialis (DLM).Weprovide confirminge vidence of the bilateral thalamofugal visual pathway ascending from nuclei of the dorsolateral thalamus (DLAmc and DLL). Projections from several brain stem structures are described, including: griseum cen‐trale (GCt), medial and lateral reticular formation (FRM and FRL), area ventralis of Tsai (AVT), n. annularis (Anl), locus coeruleus (LoC), and the avian homologue of the raphe nucleus, n. linearis caudalis (LC).The account provides a direct anatomical demonstration of a Wulst input from the basal forebrain, the somatosensory thalamus, and the brain‐stem. The projection cells in the brainstem reside in structures known to contribute to ascending catecholaminergic and serotoninergic pathways.
Ascending auditory projections to the inferior colliculus in the adult gerbil, Meriones unguiculatus
Authors: Nordeen K. W. , Killackey H. P. , Kitzes L. M. 
Published: December 2004

AbstractAscending auditory projections to the inferiorcolliculus (1C) of the adult gerbil were studied using the retrograde transport of horseradish perpxi‐dase. Our results indicate that in gerbils. The ICreceives afferent projections from most brainstem auditory nuclei. A strong contralateral projection orig‐inates in the cochlenr nuclear complex (CN). A smaller but consistent pro‐jection from all three divisions of ipsilateral CN is also present. The medial superior olive (MSO), superior parolivary nucleus, and ventral nucleus of the lateral lemniscus all maintain ipsilateral projections to the IC. Bilateral projections arise from the lateral superior olive, lateral nucleus of the tra‐pezoid body, and dorsal nucleus of the lateral lemniscus.Previous investigations in other mammalian species provide conflicting data concerning the magnitude of a direct ipsilateral projection from CN to the IC. Our quantitative data indicate that the ipsilateral projection from CN in the gerbil is nearly one third as large as the projection from ipsilateral MSO. The projection from contralateral CN is six times larger than the MSO projection. The distribution of labeled cells across the rostrocaudal extent of MSO and the three divisions of the cochlear nuclear complex are presented.
Reorganization in granuloprival cerebellar cultures after transplantation of granule cells and glia. II. Ultrastructural studies
Authors: Blank Nathan K. , Seil Fredrick J. 
Published: December 2004

AbstractCytosine arabinoside‐induced granuloprival cerebellar cultures lack both granule cells and differentiated glia and demonstrate marked synaptic reorganization. After kainic acid‐exposed cerebellar explants, which contain granule cells and mature glia, were transplanted to the granuloprival cultures, the following ultrastructural features were noted: (1) parallel fibers formed normal synapses with Purkinje cell dendritic spines as well as with basket/stellate cell somata; (2) sprouted Purkinje cell recurrent axon collateral terminals were markedly reduced in number; (3) Purkinje cells matured and lost perisomatic spines; (4) astroglia formed sheaths around Purkinje cell somata and dendrites; and (5) axonal myelination occurred. The transplanted cultures demonstrated ultrastructural restitution toward normal after addition of missing elements.