bluuebunny/crossref_metadata_2025_split huggingface dataset:
Failure of the subcallosal sling to develop after embryonic x‐irradiation is correlated with absence of the cavum septi
Authors: Schneider Bernard F. , Silver Jerry 
Published: January 2005

AbstractDuring embryonic development of the rodent forebrain, a cavity normally appears at the midline just below the corpus callosum. This cavity, the cavum septi, is present in mice by gestational day 18, but is subsequently obliterated by growth of the septal nuclei and neuropil. After x‐irradiation of pregnant mice with 125r on gestational day 14.5, the cavum septi did not develop. This dramatic developmental abnormality was accompanied by delayed fusion of the septum, and a reduction in the population of subventricular cells that normally migrate to form a sling of cells extending from the medial aspect of the lateral ventricles to the midline. In normal animals formation of the cavum septi involves degeneration of this subcallosal sling of SV cells. Thus absence of the cavum after x‐irradiation may be due to the premature killing of subventricular cells before their migration toward the midline.
Further study of the outward displacement of retinal ganglion cells during optic nerve regeneration, with a note on the normal cells of dogiel in the adult frog
Authors: Singman Eric L. , Scalia Frank 
Published: January 2005

AbstractIn a previous study we observed massive retinal ganglion cell death in adult Rana pipiens after periods of optic nerve regeneration, and reported that large numbers of the surviving cells had become displaced bodily into the inner plexiform layer of the affected eye (Scalia et al.: Brain Research 344:267–280, 1985). The outwardly displaced cells could be identified as retinal ganglion cells because they could be back‐filled with horseradish peroxidase (HRP) injected into the regenerated optic nerve. Quantitative observations on the abnormal outward displacement of ganglion cells are reported here. Parallel observations on normally displaced ganglion cells (cells of Dogiel) are also reported to clarify the distinctions between these two classes of cells.For the present work, injections of HRP of varying size were placed in the optic tectum bilaterally in 3 normal frogs and 9 frogs sustaining unilateral optic nerve regeneration. Most injections were centered at loci mapping the middle region of the nasal retina. The retinas were examined as flat‐mounts and in‐section. In 8 other frogs sustaining optic nerve regeneration, the HRP was administered bilaterally directly to the optic nerves in the orbit. Ganglion cells were labeled by retrograde transport of the HRP in the retinal ganglion cell layer in both the normal and affected eyes in areas topographically isomorphic with the tectal areas subtended by the injections. In the normal eyes, the orthotopic ganglion cells formed a strict monolayer, and virtually no cells existed in the inner plexiform layer. In the retinas sustaining optic nerve regeneration, the retinal ganglion cells abnormally displaced into the inner plexiform layer were also labeled topographically in correspondance with the injection sites.The abnormally displaced cells comprised 5.5% of the total population of surviving neurons in the retinal ganglion cell and inner plexiform layers. The mean outward dislocation of the displaced cells, as measured in one frog surviving optic nerve crush for 8 weeks, was 69.9 ± 2.4% of the distance across the inner plexiform layer, which itself was uniformly 14.3 ± 0.39 μm thick.Cells of Dogiel, which were embedded within the inner nuclear layer, were also labeled when the injections of HRP spread to include the area of representation of the optic disc. The labeled cells were restricted to a dorsal, peripapillary locus capping the optic disc. Therefore, some cells of Dogiel project to the tectum normally, but only from the central retina.Some possible mechanisms behind the abnormal postoperative displacement of the ganglion cells are discussed.
Cytoarchitecture of the human dorsal raphe nucleus
Authors: Baker Kerry G. , Halliday Glenda M. , Törk Istvan 
Published: January 2005

AbstractSerial 50 μm Nissl‐stained sections through the midbrain and pontine central gray of four adult humans (mean age 56 years, mean postmortem delay 3 hours) were analysed and the subnuclei of the dorsal raphe nucleus (DR) delineated on the basis of neuronal morphology and density. Five subnuclei were apparent: the interfascicular, ventral, ventrolateral, dorsal, and caudal. The area of each subnucleus was measured in sections selected at regular intervals throughout the length of the DR. The number of neurons was counted and their density within each subnucleus calculated. The dorsal subnucleus was the largest and contained the majority of neurons but had the lowest neuronal density. The ventrolateral subnucleus had the highest density of neurons. A total of 235,000 ± 15,000 neurons (average of 1,200 ± 200 neurons per section) were found within a volume of 71.3 ± 4.5 mm3 of DR with a mean neuronal density of 3,300 ± 200 neurons/mm3. Morphometric and morphological analysis of DR neurons revealed four distinct neuron types: round, ovoid, fusiform, and triangular. These types of neurons characterized particular subnuclei. The location and boundaries of the subnuclei of the human dorsal raphe are presented in the form of an atlas. The subdivisions described are similar to that described in other mammals. On the basis of this information the location of particular projection neurons within the human dorsal raphe can be predicted and the effects of disease on this nucleus may be forecast.
Type‐specific localization of monoamine oxidase in the enteric nervous system: Relationship to 5‐hydroxytryptamine, neuropeptides, and sympathetic nerves
Authors: Gershon M. D. , Sherman D. L. , Pintar J. E. 
Published: January 2005

AbstractThe localization in the guinea pig enteric nervous system (ENS) of monoamine oxidase (MAO) types A and B was investigated at the light and electron microscopic levels. Immunocytochemistry was used to visualize the enzyme protein and histochemistry was employed to study catalytic activity. Type specificity was achieved in histochemical studies by using deprenyl (0.5 μM) to inhibit MAO‐B or clorgyline (0.1 μM) to inhibit MAO‐A. The distribution of MAO‐B immunoreactivity in the ENS corresponded to that of the sites of MAO activity found histochemically to be inhibited by deprenyl, but not clorgyline. MAO‐B was observed to be the primary type of MAO found in the intrinsic elements of the ENS and was located in subsets of neurons in both submucosal and myenteric plexuses. MAO‐B was not demonstrated immunocytochemically or histochemically in enteric glia, nor, at the light microscopic level, was there significant MAO‐B activity or immunoreactivity in serotonin (5‐HT)‐immunoreactive neuronal cell bodies. In the submucosal plexus about 50% of the neurons expressed MAO‐B; these neurons also contained neuropeptide Y (NPY) and/or calcitonin gene related peptide (CGRP), but not substance P or vasoactive intestinal polypeptide (VIP). About 10% of myenteric neurons were intensely reactive for MAO‐B; again MAO‐B was co‐localized with NPY and/or CGRP. In contrast to intrinsic neurons, extrinsic CGRP‐immunoreactive nerve fibers contained no demonstrable MAO activity or immunoreactivity. Moreover, the sympathetic innervation, identified as varicose axons that degenerated after administration of 6‐hydroxydopamine, contained abundant MAO‐A, but no MAO‐B activity or immunoreactivity. It is concluded that MAO‐B is characteristic of a subset of intrinsic enteric neurons, while MAO‐A is confined to the sympathetic innervation, which is extrinsic. At the electron microscopic level individual cells varied greatly in their degree of immuno‐ or cytochemically demonstrable MAO‐B, which was most concentrated on the outer membranes of mitochondria. MAO‐B immunoreactivity (but not cytochemical activity) was found on mitochondria in some serotoninergic perikarya identified by the simultaneous radioautographic detection of the uptake of 3H‐5‐HT. Mitochondria in most serotoninergic axon terminals displayed both MAO‐B activity and immunoreactivity. Neurons receiving serotoninergic synapses often, but not invariably, contained MAO‐B. Inhibition of neither MAO‐B nor MAO‐A appeared to slow the disappearance of 3H‐5‐HT loaded into enteric neurons significantly, even when intraneuronal storage of 5‐HT was inhibited with tetrabenazine. Alternative pathways for 5‐HT catabolism, such as glucuronidation, which do not occur in the brain, may be available to enteric serotoninergic neurons. The role of MAO‐B in enteric neurons that are not monoaminergic but peptidergic remains to be determined.
Morphology of retinal ganglion cells in the flying fox (Pteropus scapulatus): A lucifer yellow investigation
Authors: Dann J. F. , Buhl E. H. 
Published: January 2005

AbstractThe morphology of retinal ganglion cells was determined in megachiroptera, commonly known as flying foxes. Retinal ganglion cells were intracellularly injected with the fluorescent dye Lucifer yellow in fixed retinae from adult little red flying foxes (Pteropus scapulatus) captured in their natural habitat. Ganglion cells closely resembled the three main classes of cat retinal ganglion cells, and therefore were classified into alpha‐, beta‐, and gamma‐type cells. The size of the alpha‐ and beta‐type somas and dendritic fields increased with increasing distance from the area centralis. However, this eccentricity dependence was not as pronounced as in the cat. The gamma‐type cells were sub‐divided into mono‐, bi‐, and diffusely stratified, in accordance with the ramification of their dendrites within the inner plexiform layer. The alpha‐and beta‐type cells were uni‐stratified in either the sublamina of the inner plexiform layer closest to the ganglion cell layer or in that closest to the inner nuclear layer. These laminae correspond to those in the cat retina which contain the dendritic ramifications of ganglion cells whose central receptive fields respond best to onset of light (the “on‐centre” cells), or to ganglion cells whose centres respond optimally to light being extinguished (the “off‐centre” cells). Thus the flying fox retina contains a morphological correlate of the “on”/“off” dichotomy of alpha and beta cells in the cat retina. In general the flying fox retinal ganglion cells exhibit a degree of morphological complexity reminiscent of cat retinal cells and this may reflect similar functional properties.
Multiplicity of vestibulospinal projections to the upper cervical spinal cord of the cat: A study with the anterograde tracer Phaseolus vulgaris leucoagglutinin
Authors: Donevan A. H. , Neuber‐Hess M. , Rose P. K. 
Published: January 2005

AbstractThe distribution and frequency of vestibulospinal axons and boutons in the upper cervical spinal cord of the cat were investigated. The anterograde tracer Phaseolus vulgaris leucoagglutinin (PHA‐L) was injected into discrete regions of the vestibular nuclei, including the medial and descending nuclei, as well as small regions of the lateral vestibular nucleus along its medial border with the medial vestibular nucleus. In contrast to previous reports, labelled vestibulospinal axons were not found to be restricted to the ventromedial and ventrolateral funiculi, but were also observed bilaterally in the lateral funiculi, the dorsolateral funiculi and the dorsal columns. The diameter of these axons ranged from 0.5 to 7.4 μm. Labelled boutons were found bilaterally from lamina IV to IX as well as in lamina X. Contralateral to the injection site, boutons were frequently found as far dorsal as lamina II. Ipsilaterally, boutons were found this far dorsal in only one experiment. There was a dense projection to the contralateral central cervical nucleus, while very few, if any, boutons were observed in the ipsilateral central cervical nucleus. In each experiment, the density of boutons was greater in the rostral cervical segments than in more caudal segments. The “new” vestibulospinal projections to the dorsal horn and central cervical nucleus were confirmed in separate experiments using retrograde transport of horseradish peroxidase.These results show that vestibulospinal axons project to the upper cervical spinal cord via multiple funicular paths. The rich terminations of these axons outside of the ventral horn, as well as in the neck motoneuron nuclei, indicate that vestibulospinal projections must play a wide variety of functions in addition to their well‐documented role in the direct control of head movement.
Quantitative nissl study of the neuronal types, and recognition of cytoarchitectural subdivisions, within the rabbit periaqueductal gray
Authors: Meller S. T. , Dennis B. J. 
Published: January 2005

AbstractA quantitative analysis of 4,621 Nissl‐stained neurons within the periaqueductal gray of the rabbit found that there were four main cell types (stellate/round, ovoid, spindle, and triangular) distributed throughout this complex. Further statistical analysis on these neurons confirmed that there were morphological grounds to subdivide the periaqueductal gray into four cytologically distinct regions: ventral, lateral, dorsal, and medial.Neurons in the narrow medial zone, which completely surrounds the aqueduct, were orientated essentially parallel to the aqueduct. The majority of these neurons were small, ovoid, or spindle in shape, and highly basophilic. The cells in this region had the lowest packing density of those in any periaqueductal gray subdivision. The dorsal subdivision, a small midline region, contains the largest cells of any division and the highest packing density of glial cells. The neurons in this region show no preference for orientation, tend to be round, and are moderately basophilic. Cells in the lateral zone are also quite large and demonstrate a preferred orientation either parallel or perpendicular to the aqueduct. The average cell density within lateral PAG is considerably higher than in other regions. Most of these neurons are round or ovoid, and moderately basophilic. Neurons in the ventral zone are mainly ovoid, of medium size, highly basophilic, and lie fairly sparsely arrayed and are orientated essentially parallel to the aqueductal surface.
Transcallosal non‐pyramidal cell projections from visual cortex in the cat
Authors: Peters Alan , Payne Bertram R. , Josephson Karen 
Published: January 2005

AbstractNon‐pyramidal cells with transcallosal projections were identified in the area 17/18 border region of the cat by retrograde transport of horseradish peroxidase injected into border region of the opposite hemisphere. From several hundred neurons filled with a Golgi‐like diaminobenzidine (DAB) reaction product, seven cells were identified by their radially oriented smooth dendrites as possible non‐pyramidal cells. Following thin‐sectioning and examination with the electron microscope, four of the neurons proved to be layer IV spiny stellate cells with incompletely filled dendritic spines, and two proved to be layer III pyramidal cells with an incompletely labelled apical dendrite and dendritic spines. The remaining neuron was a non‐pyramidal cell whose essentially smooth dendrites were covered with synapses, and whose cell body formed both symmetric and asymmetric synapses with presynaptic terminals. To better assess how many non‐pyramidal cells might be labelled, thin sections of the area 17/18 border were surveyed using material processed with tetramethylbenzidine (TMB), and another five labelled non‐pyramidal cells with transcallosal projections were identified by the needle‐like crystals of TMB reaction product they contained. During the study it became evident that both the DAB and TMB reaction products in the lightly labelled neurons tended to be associated with granules that are 0.5 μm or larger in diameter and that had the characteristics of lysosomes. These granules are also visible in the light microscope as dark puncta. The numbers of puncta in profiles of pyramidal and of non‐pyramidal cells in layers II/III and IVa of the area 17/18 border region and in the control acallosal region of area 17 were counted and compared. These comparisons revealed that labelled transcallosally projecting non‐pyramidal cells may constitute 10–32% of the non‐pyramidal cell population at the area 17/18 border region. Similar values were also obtained for pyramidal cells in this region. Consequently, it is concluded that significant numbers of non‐pyramidal cells have axons that project through the corpus callosum to the contralateral hemisphere.
Reorganization of persistent motoneurons in a metamorphosing insect (Tenebrio molitor L., coleoptera)
Authors: Breidbach Olaf 
Published: January 2005

AbstractThe present analysis outlines how the shape of motoneurons which persist through metamorphosis in the beetle Tenebrio molitor is regulated by cellular interactions. This study focused on the structural changes of prothoracic leg motoneurons. The fate of these neurons is described in normal metamorphic development, so as to provide a basis for experimental analysis. In a first experiment the prothoracic leg imaginal discs or part of these were extirpated in the prepupa or early pupa. In a second experiment the leg imaginal discs were rotated by 180° in early larval instars of Tenebrio; the procedure caused a threefold leg anlage. Thereafter, the treated individuals continued to develop. In both experiments the effect of the operation on the structure of the dendritic trees of the persisting motoneurons was analyzed at the imaginal stage. In the first experiment the dendritic tree of the motoneurons is locally deleted. In the second experiment the branching index (quantitative description of dendritic arborization pattern) of the dendritic tree of the persisting motoneurons increased. Both experiments provided evidence that the shape of persistent leg motoneurons is stabilized and even regulated by cellular interactions during metamorphosis. Evidence is presented that sensory neurons are effective both in stabilization and regulation of the shape of persistent motoneurons.
Ontological study of calbindin‐D28k‐like and parvalbumin‐like immunoreactivities in rat spinal cord and dorsal root ganglia
Authors: Zhang Jian‐Hua , Morita Yasuhiro , Hironaka Takashi , Emson P. C. , Tohyama Masaya 
Published: January 2005

AbstractThe calcium ion plays an important role in some critical developmental events in the nervous system, such as neurulation and neurite elongation. Therefore, as the intracellular calcium‐binding proteins calbindin‐D28k (CaB) and parvalbumin (PV) may be expressed in these developmental events. Accordingly, the ontological expression of CaB and PV was examined immunocytochemically in the spinal cord and dorsal root ganglia (DRG) of the rat, in order to evaluate the relationship between CaB and PV expression, and other important developmental events.During the ontogenesis of the spinal cord, the CaB‐like immunoreactivity was mainly observed in the cell somata. The immunoreactive cells in the ventral horn of the cervical and thoracic, lumbar, and sacral segments first appeared at embryonic day (E)‐12, E‐13, and E‐14, respectively. However, these cells were not detected in the intermediate gray matter of the same segments at E‐14, E‐15, and E‐16, respectively, and in the dorsal horn at E‐14‐E‐15, E‐16, and E‐17, respectively. The peak of immunoreactive cells, both as to number and intensity, occurred in the perinatal period. However, from postnatal day (P)‐14 on, the number and intensity of the positive cells decreased, the adult levels being reached at P‐35.The PV‐like immunoreactivity was mainly detected in the fibers and punctata during the ontogenesis of the spinal cord. The immunoreactive fibers first appeared on the surface of the dorsal horn in the cervical and thoracic segments at E‐14, then entered the dorsal horn at E‐15, and reached the intermediate gray matter and ventral horn at E‐16. The first appearance of these fibers in the same areas of the lumbar and sacral segments occurred 1 day later than in the cervical and thoracic segments. During the perinatal period, the maximum content of PV‐like immunoreactive fibers, together with many punctata, was seen in the gray matter. However, between P‐14 and P‐17, most of them lost immunoreactivity rapidly, with the exception of the medial region of the intermediate gray matter, where the PV‐immunoreactive punctata remained up to the adult stage.In DRG neurons, both CaB and PV was expressed, but in different neurons. Neurons labeled with anti‐CaB and anti‐PV sera were first detected at E‐16 and E‐14, respectively. These neurons were large or medium‐sized in the prenatal period. Small neurons were also labeled with these sera after birth. Positive neurons of different sizes in DRG increased in number in the postnatal period. Up to P‐35, the expression of CaB and PV in DRG reached the adult levels.The appearance of and developmental changes in CaB‐like and PV‐like immunoreactivities in the spinal cord and DRG may be maintained during the neurogenesis of the immunoreactive regions, suggesting the possible developmental roles of CaB and PV.
Variability in tactile projection patterns to cerebellar folia crus IIa of the norway rat
Authors: Bower James M. , Kassel Jeffrey 
Published: January 2005

AbstractTactile responses in the granule cell layers of the cerebellar hemispheres of rats are topographically arranged as a series of patches each representing a different region of the body surface. Previous observations had suggested that patches representing specific body parts recur in similar folial positions in different individuals; however, these relationships were not quantified. In this study we make inter‐animal comparisons of the detailed distribution of receptive fields in the granule cell layer of the crown of crus IIa by using physiological mapping techniques. The results suggest that maps from different individuals do, in fact, share several topological features. These include the regions of the body surface represented, the general proportions of these representations, the relative positions of patches representing the same body parts, and the organization of receptive fields within patches located in similar positions. The principal variability seen in these comparisons was in the detailed neighborhood relations between different patches. As a result of the analysis of the consistent and variable features of these maps, we propose and discuss a new role for these cerebellar regions in coordinating the acquisition of tactile sensory information.