bluuebunny/crossref_metadata_2025_split huggingface dataset:
The vestibular nuclei in the macaque monkey
Authors: Brodal A. 
Published: January 2005

AbstractThe topography and the main features of the cytoarchitecture of the vestibular nuclear complex in the macaque monkey have been studied in serially cut, Nissl‐stained, transverse, parasagittal and horizontal sections. In addition to the four main vestibular nuclei, the topographically closely related small cell groups (f, 1, x, y, and z), distinguished by Brodal and Pompeiano (1957) in the cat, have been considered and illustrated.The vestibular nuclear complex in the macaque in general corresponds in topography and architecture to the situation described in some other mammals on which information is available, such as opossum, rabbit, cat,Galago, and man. Some dissimilarities in detail are found. For example, in man the lateral vestibular nucleus differs somewhat from the general pattern, especially in its position, and the small group f, fusing with the descending nucleus, appears to be indistinct; likewise the group y. The latter and the group z appear to be particularly well developed and easily distinguished in the macaque.The question of whether cytoarchitectonic areal differences within the vestibular nuclear complex can be correlated with differences in connections is discussed. Also in this respect there appears to be a general similarity between observations in the macaque and in other mammals. A correlation is most evident in the superior vestibular nucleus, and is rather clear in the medial and lateral vestibular nuclei and for the groups f, x, y, and z, whereas no such correlation can be found in the descending (inferior) nucleus. For several reasons it is difficult to draw reliable conclusions about comparative anatomical trends in the phylogenesis of the vestibular nuclear complex.
6‐Hydroxydopamine induced ectopia of external granule cells in the subarachnoid space covering the cerebellum. II. Differentiation of granule cells: A scanning and transmission electron microscopic study
Authors: Mangold Ulrich , Sievers Jobst , Berry Martin 
Published: January 2005

AbstractThe present report describes the morphological differentiation of ectopic granule cells from external granule cells that have been induced to escape from the cerebellar cortex into the subarachnoid space by injecting neonatal rats with 100 μg 6‐hydroxydopamine (6‐OHDA) into the cisterna magna.The following cell types were observed in the period between 5 and 25 days postinjection (dpi): (1) unipolar cells with one process bearing a growth cone at its tip; (2) bipolar cells with two thin beaded processes originating from opposite cell poles, bearing growth cones at their tips; (3) bipolar cells with a T‐like process at one pole and a short process lacking a terminal growth cone at the opposite pole; (4) multipolar cells with one thin beaded process and two or more short processes bearing growth cones of a different morphology at their tips; (5) intermediate stages. In the late second week p.i., cell aggregates were observed that continually increased in size up to 30 dpi. On the basis of our light, transmission, and scanning electron microscopic findings, we interpret these cell types to be equivalent to the individual stages of granule cell differentiation that characterize axon formation, migration, and aggregation.In the period between 30 and 365 dpi, granule cells were almost exclusively organized into cell colonies of different sizes, but small cell clusters and single granule cells exhibited the scanning electron microscopic features of adult granule cells, i.e., a small spherical cell body, a single axon with parent axonal stem, T‐junction, and parallel fiber, and dendrites engaged in synaptic glomeruli. The parallel fibers ran in fasciculi of different sizes, often parallel to each other, but without preferential orientation over the cerebellar surface.During migration and aggregation, the granule cells and their processes were associated with a substrate of glial sheets that in turn were connected to intracortical Bergmann glia fibers. Our findings indicate that (1) granule cells differentiate normally in an ectopic environment in the presence of glia, (2) ectopic Bergmann glia contain no directional information to guide aberrant migratory granule cells to their correct destination, (3) granule cells can survive outside the brain parenchyma for periods up to one year (the longest postinjection interval studied).
Hypomyelination in the peripheral nervous system of shiverer mice and in Shiverer ↔ Normal chimaera
Authors: Peterson A. C. , Bray G. M. 
Published: January 2005

AbstractIn shiverer mice, the P1 component of myelin basic protein (MBP) is deficient in both the central nervous system (CNS) and peripheral nervous system (PNS) but compact myelin is more grossly defective in the CNS. In the PNS, myelin exhibits a normal periodic structure, and although examples of subtle abnormalities of shiverer Schwann cell ultrastructure have been described previously, myelin thickness has been reported as unremarkable when observed by light microscopy.We report, a quantitative investigation of the myelin sheath thickness of shiverer Schwann cells in which a mild but apparently consistent hypomyelination of axons ensheathed by shiverer Schwann cells was observed. This abnormality was expressed both in the peripheral nerves of a homozygous shiverer mouse and in the shiverer Schwann cells populating the mosaic nerves of a mature ↔ shiverer normal mouse chimaera. In addition, multiple interlamellar gaps was found to be a highly consistent feature of shiverer myelin.These observations extend the description of the peripheral nerve defects expressed in shiverer mice and further define these abnormalities as direct consequences of the shiverer Schwann cells' intrinsic genotype. In light of these results, a significant role for P1 in the formation and/or maintenance of normal myelin in the PNS is suggested.
Luteinizing hormone releasing hormone containing synapses in the diagonal band and preoptic area of the guinea pig
Authors: Silverman Ann‐Judith 
Published: January 2005

AbstractLight microscopic immunocytochemical processing of the region of the ventral diagonal band of Broca (vertical limb) and the medial preoptic area of the guinea pig for LHRH revealed complex axonal bundles. The axons were of several different shapes and widths and showed varicosities of varying form. When such tissue was embedded and processed for electron microscopic localization of immunoreaction product, numerous LHRH‐positive synapses were seen. The synapses were made by large varicosities. They were all axodendritic and showed a well‐defined synaptic cleft, as well as a clustering of immunoreactive large granules and immunonegative small, clear vesicles. Postsynaptic densities were either very small or absent. These data show that LHRH is present in direct synapses within the CNS and is, therefore, in a position to be released and act as a neurotransmitter/neuromodulator as well as a neurohormone.
Changes in the topographically organized connections between the nucleus isthmi and the optic tectum after partial tectal ablation in adult goldfish
Authors: Dunn‐Meynell A. A. , Sharma S. C. 
Published: January 2005

AbstractThe projection of the nucleus isthmi to the ipsilateral optic tectum was examined in normal goldfish. This was compared to the projection in animals in which the entire visual field had been induced to compress onto a rostral half tectum by caudal tectal ablation. The isthmo‐tectal projection was examined by making localized injections of horseradish peroxidase into the optic tecta and observing the patterns of labeled cells within the nucleus isthmi. The teleost nucleus isthmi consists of a cell sparse medulla covered by a cellular cortex, which is thick on the rostral, medial, and dorsal surfaces of the nucleus. Almost all isthmic cells projecting to the tectum were located in the area of thick cortex. In normal fish, rostral tectal injections labeled cells in the rostroventral portion of the thick cortex; injections midway in the rostrocaudal tectal axis labeled more caudodorsally located cells, and caudal tectal injections labeled cells a little further caudally in extreme dorsal cortex. The rostroventral to caudodorsal isthmic axis was therefore seen to project rostrocaudally along the tectum. This topography contrasts somewhat with the situation seen in amphibia where the rostrocaudal tectal axis receives projections from the rostrocaudal isthmic axis. In fish with half‐tectal ablations, injections near the caudal edge of the half tectum (at a site that had originally been midtectal) labeled cells that had previously projected to caudal tectum. Rostral tectal injections in fish with compression of the visual field gave a normal pattern of labeled isthmic cells. The results indicate that a topographically ordered isthmo‐tectal projection exists in goldfish that may be induced to compress onto a half tectum.
The distribution of enkephalinlike immunoreactivity in the telencephalon of the adult and developing domestic chicken
Authors: Reiner Anton , Davis Brian M. , Brecha Nicholas C. , Karten Harvey J. 
Published: January 2005

AbstractImmunohistochemical techniques were used to determine the distribution of enkephalinlike immunoreactivity in the telencephalon of chicken. The densest accumulation of enkephalinergic neurons and fibers was observed within the paleostriatal complex, the avian equivalent of the mammalian basal ganglia. Numerous small enkephalinergic neurons were observed in both lobus parolfactorius (LPO) and the paleostriatum augmentatum (PA), the two components of the small‐celled portion of the paleostriatal complex. The enkephalinergic neurons of LPO‐PA appeared to give rise to a dense plexus of enkephalinergic fibers within the large‐celled zone of the paleostriatal complex, the paleostriatum primitivum (PP). The distribution of enkephalin within the avian paleostriatial complex, when compared to the distribution of enkephalin within the mammalian basal ganglia, supports previous proposals that PP is comparable to the mammalian globus pallidus and that PA‐LPO are comparable to the caudate‐putamen (Karten and Dubbeldam, '73; Kitt and Brauth, '81; Parent and Olivier, '70; Reiner et al., '83). Observations on the development of enkephalinlike immunoreactivity within the chicken paleostriatal complex also support the suggestion that the major component nuclei of the avian paleostriatal complex have correspondents within the mammalian basal ganglia.Enkephalinlike immunoreactivity was also observed within cell bodies and fibers in other portions of the avian telencephalon. Within the ventrolateral telencephalon, the nucleus accumbens, nucleus of the diagonal band, and tuberculum olfactorium contained enkephalinergic cell bodies and fibers while only enkephalinergic fibers were observed in the portion of the avian telencephalon that has been termed the ventral paleostriatum (Kitt and Brauth, '81; Reiner et al., '83). Within the medial wall of the telencephalon, enkephalinergic fibers were observed in the lateral septal nucleus, while enkephalinergic cell bodies and fibers were observed in the parahippocampal area. Little enkephalinlike immunoreactivity was observed dorsal to the paleostriatal complex except in the hyperstriatum dorsale. Within the hyperstriatum dorsale, a band of enkephalinergic neurons appeared to give rise to an overlying parallel band of dense enkephalinergic fibers.The distribution of enkephalinlike immunoreactivity within the avian telencephalon thus shows remarkable similarity to that seen in the mammalian telencephalon. The largest accumulation of enkephalinlike immunoreactivity within the telencephalon of both vertebrate classes appears to be found within the ventrolateral wall of the telencephalon, including the basal ganglia. In comparison, much less enkephalinlike immunoreactivity is observed in either the mammalian neocortex or in the avian correspondent of mammalian neocortex.
The glial reaction in the course of axon regeneration: A stereological study of the rat hypoglossal nucleus
Authors: Reisert I. , Wildemann G. , Grab D. , Pilgrim Ch. 
Published: January 2005

AbstractBoth hypoglossal nuclei were examined by electron microscope stereology after unilateral axotomy. The principal aim of this study was a quantitative assessment of the accompanying glial reaction. Volume densities (%) of neuronal and glial perikarya, as well as their processes, were evaluated in terms of volume plus surface densities (mm−1). In addition, specific surfaces (surface to volume ratio) of these neuronal and glial processes were assessed.First, a temporary decrease of dendritic volume density was detected on the ipsilateral side only. Further, the astrocytic reaction displayed differences between stem and lamellar processes. One day after axotomy, a bilateral decrease of volume density, as well as surface density of stem processes, was observed, yet their normal dimensions soon were reestablished. However, a more severe lamellar process reaction was evident. During the first 4 days, a significant increase of volume density and surface density was apparent. In the contralateral hypoglossal nucleus, this glial reaction also occurred but disappeared by day 14, whereas the ipsilateral nucleus continued to display a severe reaction of lamellar processes, only returning to normal status at day 77. In addition, a transient, severe reaction of presumptive microglia was established by employing the volume density and surface density quantitation procedure. Nevertheless, in comparison with the volume and surface contribution of astrocytic processes, the presumed microglial component was minimal.This study indicates a two‐step involvement of astrocytes in regenerative repair. Namely, the first phase seems to result in an increase of lamellar processes through reshaping of the stem process. Following this, apparently a shift to de novo synthesis of astrocytic cytoplasmic and membrane constituents could occur, hence inducing a transient astrogliosis. The present investigation clearly indicates an essential supportive role of astroglia in the time course of regenerative processes initiated by hypoglossal nerve axotomy. Given such isolation of regenerating neurons, the microglial contribution to this regeneration probably is negligible.
Localization of sympathetic postganglionic and parasympathetic preganglionic neurons which innervate different regions of the dog heart
Authors: Hopkins David A. , Armour J. Andrew 
Published: January 2005

AbstractThe locations of sympathetic postganglionic and parasympathetic preganglionic neurons projecting to the heart have not yet been clearly established. Therefore, aliquots of horseradish peroxidase (HRP) were injected into specific regions of the heart, intraventricular cavity, pericardial sac, aortic arch, and the skin in 27 dogs. Following injections into the heart, aorta, or pericardial sac, retrogradely labeled neurons were present in the greatest numbers in the middle cervical ganglia bilaterally. Labeled neurons were located in the cranial poles of the stellate ganglia bilaterally and occasionally in the superior cervical ganglia. Labeled cells were also found in small ganglia located along cardiopulmonary nerves. Injections of HRP into specific areas of the heart did not result in labeling of cells in specific loci of the thoracic or cervical sympathetic ganglia. When the ansae were cut on one side, no labeled cells were found in the ipsilateral stellate ganglion or upper thoracic chain. Following injections into the skin of the left elbow or left cranial nipple, labeled cells were found in the stellate ganglia and the sympathetic chain and in one case in the middle cervical ganglion as well. These data suggest that postganglionic sympathetic neurons which project efferent axons to a specific cardiac region are not located in a specific region of a sympathetic ganglion or a specific sympathetic ganglion. Rather, neurons in one region of a sympathetic ganglion project axons to widespread areas of the myocardium. Sympathetic postganglionic neurons in the stellate ganglion or sympathetic chain project their axons to the heart via the subclavian ansae or interganglionic nerves, not via nerves arising directly from the sympathetic chain.Small numbers of labeled neurons were found in the medulla oblongata, thus indicating that in comparison to sympathetic postganglionic neurons relatively few preganglionic parasympathetic neurons project directly to the heart. When labeled cells were present in the medulla, the majority were located in the ventrolateral nucleus ambiguus.
Mapping the body representation in the SI cortex of anesthetized and awake rats
Authors: Chapin John K. , Lin Chia‐Sheng 
Published: January 2005

AbstractWe have used single unit recording techniques to map the representation of cutaneous and joint somatosensory modalities in the primary somatosensory (SI) cortex of both anesthetized and awake rats. The cytoarchitectonic zones within the rat SI were divided into the following main categories: (1) granular zones (GZs)–areas exhibiting koniocortical cytoarchitecture (i.e., containing dense aggregates of layer IV granule cells), (2) perigranular zones (PGZs)–narrow strips of less granular cortex surrounding the GZs, and (3) dysgranular zones (DZs)–large areas of dysgranular cortex enclosed within the SI. The narrow strip between the SI and the rostrally adjacent frontal agranular cortex was termed the “transitional zone” (TZ).Initial computer‐based studies of the properties of cutaneous receptive fields (RFs) in SI showed that, although there were differences in reponse threshold, adaptability, frequency response, and overall RF size and shape of adjacent neurons, the size and location of the “centers” of the RFs were quite constant and were similar to those seen in multiple unit recordings. The same was true of RFs of single neurons recorded through different anesthetic states.The body representation in SI was first mapped by determining single unit and unit cluster RFs within a total of 2,170 microelectrode penetrations in barbiturate‐anesthetized rats. Cutaneous RFs in the GZs were quite discrete. Thus, a single, finely detailed, continuous map of the cutaneous periphery was definable within the GZs themselves. Only the forepaw had a double representation. RFs in the PGZs were larger and more diffuse, but since they covered roughly the same skin areas as the RFs in the most closely adjacent GZs, they fit into the same body map. Neurons in the DZs were unresponsive to any sensory stimuli in the anesthetized animal.In chronically implanted, freely moving, awake animals cutaneous RFs were larger and more volatile than in the anesthetized, but the accuracy of the map was clearly preserved by the fact that the locations of the RF centers (which often must be defined quantitatively) were unchanged. The PGZs and DZs in the awake animals exhibited a multimodal convergence of cutaneous and joint movement RFs within single vertical penetrations, or even on single neurons. Directionally specific and bilateral cutaneous RFs were also observed in the DZs. It was concluded the DZs are more associational or integrative areas within the SI, but they could not be shown to comprise a distinct and separate body representation. The rat SI cortex therefore appears to contain, within a single overall body map, both granular and dysgranular cytoarchitectonic zones. Not only are different sensory modalities subserved within this map, but also different levels of physiological complexity and anesthesia sensitivity.
Fine structure of histaminergic neurons in the caudal magnocellular nucleus of the rat as demonstrated by immunocytochemistry using histidine decarboxylase as a marker
Authors: Hayashi Hideyuki , Takagi Hiroshi , Takeda Noriaki , Kubota Yoshiyuki , Tohyama Masaya , Watanabe Takehiko , Wada Hiroshi 
Published: January 2005

AbstractThe morphology of histamine‐containing neurons in the caudal magnocellular nucleus was light and electron microscopically examined by means of peroxidase‐antiperoxidase (PAP) immunocytochemistry with histidine decarboxylase (HDC) as a marker. HDC‐like immunoreactive (HDCI) neurons had large (25–30 μm in diameter) perikarya from which two to four primary dendrites arose. The perikarya had a nearly round nucleus and well‐developed Golgi apparatus in addition to a large number of mitochondria and rough endoplasmic reticulum. Immunoreactive endproducts were found diffusely throughout the perikarya, dendrites, and axons. HDCI neurons made synaptic contact with nonreactive axon termminals on the perikarya and dendrites. In addition, the HDCI neurons very frequently formed puncta adherentia with neuronal elements, either HDCI or nonreactive, or glial cells. Most of the HDCI axon terminals serially observed under electron microscopy did not exhibit typical synaptic contact in the caudal magnocellular nucleus. These findings suggest the nonsynaptic release of histamine in the caudal magnocellular nucleus.
The cortical projection of the basolateral amygdaloid nucleus in the rat: A retrograde fluorescent dye study
Authors: Sripanidkulchai K. , Sripanidkulchai B. , Wyss J. M. 
Published: January 2005

AbstractThe fluorescent dye, retrograde labeling technique was used to determine the extent of the projection from the basolateral nucleus of the amygdala to the neocortex in the rat. Each rat received a single cortical injection of fast blue, and in one‐half of the animals, a subsequent injection of nuclear yellow was placed in a different cortical region. An analysis of the results demonstrates that the projection to the midline cortex arises in the medial neurons within the caudal two‐thirds of the basolateral nucleus. This projection is directed to the anterior cingulate cortex, but not to the posterior cingulate cortex. The primary motor cortex receives a basolateral amygdala projection which originates from neurons in two areas, (1) the medial part of the anterior one‐third of the nucleus and (2) the center (in the lateral to medial axis) portion of the posterior two‐thirds of the nucleus. The latter neurons are situated lateral to the neurons projecting to the cingulate cortex. Somatosensory cortex injections label many fewer basolateral nucleus neurons than do motor cortex injections, but these neurons are located in a position similar to that of those labeled by motor cortex injections. Finally the gustatory cortex, which lies just dorsal to the rhinal sulcus, receives a basolateral projection from neurons in the lateroventral one‐half of the basolateral nucleus. These results demonstrate that the basolateral nucleus gives rise to a rather widespread and topographically organized projection to the anterior half of the neocortex of the rat.