bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cell death in the developing retinal ganglion cell layer of the wallaby Setonix brachyurus
Authors: Dunlop S. A. , Beazley L. D. 
Published: January 2005

AbstractThe distribution and number of dying cells in the developing retinal ganglion cell layer of the wallaby Setonix brachyurus were assessed by using cresyl violet stained tissue. The density of dying cells has been expressed per 100 live cells for the entire retinal surface, data being presented as a grid of 500 μm squares. For statistical analysis, retinae were divided into 8 regions; dorsal, ventral, nasal, and temporal quadrants, each further divided into center and periphery. This method allowed comparison of the extent of cell death at different retinal locations as the high density area centralis of live cells developed temporal to the optic disk from 60 days onward.Between 30 and 70 days, dying cells were seen across the entire retina; beyond 100 days very few were seen. Initially, there was a significantly higher incidence of dying cells in the central retina compared to the periphery, whereas from 50 days this situation was reversed. Analysis of the central retina before and during area centralis formation consistently indicated a significantly lower number of dying cells per 100 live cells in temporal compared to other retinal quadrants. This differential pattern suggests that cell death lowers live cell densities less in the emerging area centralis than elsewhere, and therefore must play a part in establishing live cell density gradients. However, we cannot exclude the possibility that other factors are also instrumental. Indeed, factors such as areal growth (Beazley et al., in press) presumably operate at later stages since live cell density gradients continue to be accentuated even after cell death is complete.Numbers of dying cells peaked by 50 days, reaching approximately 1% of the live cell population. At this stage, counts were also maximal for live cells with values up to 30% above the adult range.
Effects of prenatal irradiation on the development of cerebral cortex and corpus callosum of the mouse
Authors: Schmidt Sergio L. , Lent Roberto 
Published: January 2005

AbstractDefects of the cerebral cortex and corpus callosum of mice subjected prenatally to gamma irradiation were evaluated as a function of dose and of embryonic age at irradiation. Pregnant mice were exposed to a gamma source at 16, 17, and 19 days of gestation (E16, E17, and E19, respectively), with total doses of 2 Gy and 3 Gy, in order to produce brain defects on their progeny. At 60 postnatal days, the brains of the offspring were analyzed qualitatively and quantitatively and compared with those of nonirradiated animals. Mice irradiated at E16 were all acallosal. Those that were exposed to 2 Gy displayed an aberrant longitudinal bundle typical of other acallosals, but this was not the case in those irradiated with 3 Gy. The corpus callosum of animals irradiated at E17 with 3 Gy was pronouncedly hypotrophic, but milder effects were observed in the other groups. Quantitative analysis confirmed a dependence of callosal midsagittal area upon dose and age at irradiation, and, in addition, indicated an interaction between these variables. The neocortex of irradiated animals was hypotrophic: layers II‐III were much more affected than layer V, and this was more affected than layer VI. Quantitative analysis indicated that this effect also depended on dose and age at irradiation and that it was due to a loss of cortical neurons. Furthermore, a positive correlation was found between the number of neurons within layers II‐III, and V and the midsagittal area of the corpus callosum. Ectopic neurons were found in the white matter and in layer I of animals irradiated at E16 and E17, indicating that fetal exposure to ionizing radiation interfered with the migration of cortical neuroblasts.
Immunocytochemical studies of vasotocin, mesotocin, and neurophysins in the Xenopus hypothalamo‐neurohypophysial system
Authors: Conway Kevin M. , Gainer Harold 
Published: January 2005

AbstractMesotocinergic and vasotocinergic neurons, which constitute the principal neurons in the hypothalamo‐neurohypophysial system in Xenopus, were studied by immunocytochemical techniques. Antibodies that could unequivocally distinguish mesotocin, vasotocin, and their respective neurophysins were used in these studies. A monoclonal antibody directed at rat oxytocin‐associated neurophysin (PS‐36) detected an antigen that was colocalized with vasotocin, whereas a monoclonal antibody to rat vasopressin‐associated neurophysin, (PS‐45) crossreacted with an antigen in mesotocinergic cells. As vasotocin is regarded as an evolutionary precursor of vasopressin, and as mesotocin is usually associated with oxytocin, we were surprised to see this apparent epitope switch in the associated neurophysins. One interpretation of this epitope switch is that the final exons encoding for the carboxy‐terminals of the mammalian neurophysins, which contain the PS‐45 and PS‐36 antibody epitopes, are in reversed positions in Xenopus. Approximately 4,000 mesotocinergic and vasotocinergic neurons and their fibers were topographically mapped in the Xenopus hypothalamus. The two types of neurons were intermingled and scattered throughout a large contiguous region including but not limited to the preoptic recess. Small, medium size, and large cells contained these antigens. Immunoreactive fibers were seen in the preoptic area, the neurohypophysial tract, the median eminence, and the neural lobe of the pituitary. The neurophysin‐specific monoclonal antibodies have several advantages as phenotypic markers in development; i.e., high titer, low background, and affinity for the prohormone forms as well as for the fully processed neurophysin polypeptides. Their antigens are related gene products whose expression is central to the identity of the two cell types and whose expression is differentially controlled in development. This characterization of their adult distribution provides a basis for future studies of the development of peptidergic phenotype in the central nervous system of Xenopus.
Organisation of subcortical pathways for sensory projections to the limbic cortex. I. Subcortical projections to the medial limbic cortex in the rat
Authors: Thompson Scott M. , Robertson Richard T. 
Published: January 2005

AbstractSubcortical afferent projections to the medial limbic cortex were examined in the rat by the use of retrograde axonal transport of horseradish peroxidase. Small iontophoretic injections of horseradish peroxidase were placed at various locations within the dorsal and ventral cingulate areas, the dorsal agranular and ventral granular divisions of the retrosplenial cortex and the presubiculum. Somata of afferent neurons in the thalamus and basal forebrain were identified by retrograde labeling.Each of the anterior thalamic nuclei was found to project to several limbic cortical areas, although not with equal density. The anterior dorsal nucleus projects primarily to the presubiculum and ventral retrosplenial cortex; the anterior ventral nucleus projects to the retrosplenial cortex and the presubiculum with apparently similar densities; and the anterior medial nucleus projects primarily to the cingulate areas.The projections from the lateral dorsal nucleus to these limbic cortical areas are organized in a loose topographic fashion. The projection to the presubiculum originates in the most dorsal portion of the lateral dorsal nucleus. The projection to the ventral retrosplenial cortex originates in rostral and medial portions of the nucleus, whereas afferents to the dorsal retrosplenial cortex originate in caudal portions of the lateral dorsal nucleus. The projection to the cingulate originates in the ventral portion of the lateral dorsal nucleus.Other projections from the thalamus originate in the intralaminar and midline nuclei, including the central lateral, central dorsal, central medial, paracentral, reuniens, and paraventricular nuclei, and the ventral medial and ventral anterior nuclei. In addition, projections to the medial limbic cortex from the basal forebrain originate in cells of the nucleus of the diagonal band. Projections to the presubiculum also originate in the medial septum.These results are discussed in regard to convergence of sensory and nonsensory information projecting to the limbic cortex and the types of visual and other sensory information that may be relayed to the limbic cortex by these projections.
Afferent and efferent connections of the oculomotor cerebellar vermis in the macaque monkey
Authors: Yamada Jinzo , Noda Hiroharu 
Published: January 2005

AbstractSaccadic eye movements were evoked with weak currents applied to a circumscribed vermal area. The area was confined to lobule VII in the majority of the monkeys and coincided with the distribution of saccade‐related neural activity. We defined this area as the oculomotor vermis and studied its anatomical connections with wheat germ‐agglutinin conjugated horseradish peroxidase (WGA/HRP) and HRP.When injected HRP was confined to the oculomotor vermis, most labeled Purkinje axons terminated ipsilaterally in an ellipsoidal region in the mediocaudal aspect of the fastigial nucleus. Retrogradely labeled cells were found in two relatively circumscribed regions in the fastigial nucleus: one group was in the lateral half of the ellipsoidal terminal region and the other group was in a spherical region near the lateral margin of the nucleus.Following the injection of HRP into the oculomotor vermis, the largest population of retrogradely labeled neurons was found in the nucleus reticularis tegmenti pontis. Labeled cells were located only in the medial and dorsolateral portions of the nucleus. The cell aggregates in the dorsolateral portion merged with densely labeled cells of the processus tegmentosus lateralis. The second largest population of labeled cells was found in the pontine nuclei. Approximately 28% of the labeled pontine cells aggregated in the paramedian pontine nucleus, whereas the other labeled pontine cells were widely distributed in the dorsal part of the pontine peduncular nucleus and the dorsolateral pontine nucleus. Labeled cells were scattered also in the pontine raphe, the paramedian pontine reticular formation, and the interfascicular nucleus at the rostral level of the hypoglossal nucleus. Fewer labeled cells were discovered in the vestibular nuclear complex and the prepositus hypoglossi. In the inferior olivary nucleus, labeled cells were located in the subnucleus b of the medial accessory nucleus.
Parasagittal organization of the rat cerebellar cortex: Direct correlation between antigenic purkinje cell bands revealed by mabQ113 and the organization of the olivocerebellar projection
Authors: Gravel Claude , Eisenman Leonard M. , Sasseville Rachel , Hawkes Richard 
Published: January 2005

AbstractThe Purkinje cells of the cerebellar cortex and the cortical afferent and efferent projections are organized into parallel parasagittal zones. The parasagittal organization is clearly revealed by immunocytochemistry with a monoclonal antibody, mabQ113. The mabQ113 antigen is confined to a subset of Purkinje cells that are clustered together to form an elaborate, highly reproducible pattern of bands and patches, interspersed with similar mab‐Q113– regions. The mabQ113 + territories have been classified into seven parasagittal bands (P1 + ‐P7 +) in each hemicerebellum. The degree of correspondence between the compartments revealed by the anterograde labeling of the olivocerebellar projection and by mabQ113 immunocytochemistry has been explored in the adult rat. Horseradish peroxide‐wheat germ agglutinin conjugate was injected as an anterograde tracer into the inferior olivary complex. When the injection site did not encompass all the olive, an incomplete, patchy labeling of the molecular layer was seen in the cerebellar cortex. Labeled zones of the molecular layer were interrupted by unlabeled regions to give a pattern of parasagittal cortical bands. The positions of these bands were compared with the distribution of the mabQ113 + antigenic bands as seen on the two adjacent sections. Labeled climbing fibers were found to terminate on both mabQ113 + and mabQ113 ‐ Purkinje cell zones. The mabQ113 +/mabQ113‐ boundaries and the bands of climbing fibers seen by using the anterograde tracer typically coincide. The one consistent exception is the midline band of mabQ113 + Purkinje cells, P1 +.The normal olivocerebellar projection is exclusively contralateral and the climbing fiber projection to the paramedian vermis splits P1 + down the middle, implying that it consists of two adjacent mabQ113+ bands not separated by mabQ113‐territory. It is likely that the climbing fiber projection to the cerebellar cortex and the distribution of the two Purkinje cell phenotypes share a common compartmental organization.
Influence of nerve growth factor on chick trigeminal motor nucleus explants
Authors: Heaton Marieta Barrow 
Published: January 2005

AbstractExplants of the metencephalic basal plate from stage 11 (40–hour) chick embryos containing the trigeminal (V) motor nucleus were cultured in standard control medium, in medium supplemented with nerve growth factor (NGF), in medium supplemented with NGF and specific antibodies to NGF (anti‐NGF), and in medium supplemented with anti‐NGF alone. The explants grown in the presence of NGF displayed an enhanced density and complexity of neuritic outgrowth, with this growth significantly surpassing that seen in the control group (p≥.001). The explants grown in NGF plus anti‐NGF and those grown in anti‐NGF alone did not differ from controls. The results indicate that this early cholinergic population is specifically responsive to NGF. This finding is consistent with recent studies in which NGF receptor binding has been found in this and other early brainstem and spinal cord motor neuron populations. The possible relevance of these observations to the normal sequence involved in the development of the V motor nucleus is discussed, particularly as they may relate to the relationship between the V ganglion and the developing V motor population.
Deafferentation‐induced alterations in the rat dorsal horn: II. Effects of selective poisoning by pronase of the central processes of a peripheral nerve
Authors: LaMotte Carole C. , Kapadia Shanta E. 
Published: January 2005

AbstractStudies of deafferentation and regeneration, as well as studies requiring several tracing techniques, would benefit from availability of a substance that would selectively lesion the central components of a single peripheral nerve. Pronase, a combination of proteolytic enzymes, was tested for this purpose.Three weeks following microinjection of Pronase (5–25 mg) into the rat sciatic nerve, many ganglia cells in the L3‐L5 ganglia were degenerated. Degeneration of primary afferents also was evident in the dorsal horn, as detected by silver Fink‐Heimer methods. Patterns of terminal fields coincided with those mapped in normal rats for the sciatic nerve by using HRP transport.Ultrastructural changes were similar to those seen at 3 weeks following sciatic nerve section or rhizotomy, as described in our companion paper. However, degenerative changes following Pronase injection of the sciatic nerve were quantitatively greater than those following sciatic nerve section alone. Degenerating terminals were either electron lucent and swollen, electron dense, or filamentous with loss of vesicles. Postsynaptic dendrites, and occasionally somata, also showed signs of degeneration. Some became electron dense, others accumulated osmiophilic floccular material, but most became electron lucent and developed large membrane‐bound cavities. Glial processes expanded around degenerating elements, wrapping around both terminals and dendrites. Glial sheets covered denervated dendritic and somatic spines, separating them from their terminals. Labyrinth formations of glial sheaths around debris were also found. Pronase appears to mimic the effects of mechanical destruction of primary afferents, but when compared to rhizotomy, is selective for the afferents of a single nerve, and, when compared to nerve section, produces a greater effect. Further, the substance is relatively safe for investigators compared to other toxins such as ricin.
Structure‐function relationships in the rat brainstem subnucleus interpolaris: II. Low and high threshold trigeminal primary afferents
Authors: Jacquin Mark F. , Stennett Richard A. , Renehan William E. , Rhoades Robert W. 
Published: January 2005

AbstractPrior studies indicate that vibrissa, guard hair, hairy skin, mucosa, and nociceptive trigeminal primary afferents give rise to morphologically distinct terminal arbors in the medullary dorsal horn. The present study describes the extent to which similar structure‐function relationships exist in the rostrally adjacent subnucleus interpolaris (SpVi). Seventy‐three axons were physiologically characterized and visualized by standard intra‐axonal HRP labeling techniques. They responded to guard hair (GH) or vibrissa (VIB) deflection; gentle pressure applied to hairy skin (HS), glabrous skin (GS), lingual mucosa (LM), or an incisor (PER); or a noxious pinch of the face (NOX). Response latencies to trigeminal ganglion shocks were equivalent for all categories with low threshold receptive fields (mean = 0.44 ms), and these were significantly shorter than those of fibers with high threshold NOX receptive fields (mean = 0.88 ms). All axons gave off transversely oriented collaterals into SpVi with rostrocaudal discontinuities in their arbors. Collaterals were topographically organized. Axons innervating the rostral mouth and face terminated medially, and those that supplied the caudal face innervated successively more lateral SpVi. The dorsal face was represented in the ventral SpVi, whereas the ventral face and mouth were represented more dorsally. This transverse topography extended largely throughout the rostrocaudal extent of SpVi.VIB, GH, GS, and LM collaterals had similar configurations with circumscribed arbors. HS, PER, and NOX arbors had a “stringy” shape without a clear terminal focus, save for the fact that PER and NOX collaterals often terminated in rostrally displaced substantia gelatinosa at the level of the caudal SpVi. Analysis of variance, considering only those data from mystacial VIB, GH, and HS fibers, indicated significant differences for all of the following measures: number of collaterals, number of boutons per collateral, arbor area, arbor circumference, and arbor circularity (form factor). A similar analysis, considering all fiber types, indicated significant differences for only the following measures: number of collaterals, arbor area, and arbor circumference. Individual group comparisons between the more heavily sampled functional categories indicated that GH afferents had significantly.
Topographic and zonal organization of the olivocerebellar projection in the reeler mutant mouse
Authors: Blatt Gene J. , Eisenman Leonard M. 
Published: January 2005

AbstractThe organization of the olivocerebellar projection in the homozygous reeler mouse (rl/rl) was studied with the use of microinjections of 3H‐leucine in different regions of the inferior olivary complex (IO) or horseradish peroxidase conjugated with wheat germ agglutinin (WGA‐HRP) into medial, intermediate, or lateral regions of the reeler cerebellum. The purpose of this investigation was to determine the pattern of termination of olivocerebellar climbing fibers (CFs) in the cerebellum via an anterograde tracing technique, and to determine the topographic organization of the olivocerebellar projection via both anterograde and retrograde methods. The inferior olive injections were made via the ventral (i.e., retropharygeal) approach to the IO to minimize diffusion into other brainstem precerebellar nuclei and thus to ensure accurate well‐restricted, injection sites. Labeled CF terminals were seen in both the superficial Purkinje cell (PC) layer (normally positioned PCs) and around PCs in the granular layer and central masses (ectopic PCs). The pattern of labeling is suggestive of orthogonal organization, in that vertical columns of cells are labeled. This is especially apparent in the medial PC group, where at least three bands are identified. Within an orthogonal band, CF terminals are seen around both superficial and deep Purkinje cells. Our data indicate that olivocerebellar topography is generally similar in reeler and normal mice despite severe abnormalities in target cell position in the reeler. The medial cerebellar region receives input from the caudal two‐fifths of the medial accessory olive (MAO). The intermediate PC cluster receives input from more rostral portions of all three olivary divisions (MAO), principal olive [PO] and dorsal accessory olive [DAO], while rostral portions of MAO and PO project to the lateral cerebellum. These results indicate that the zonal organization of the olivocerebellar projection in the adult reeler exhibits a pattern generally similar to that seen in normal mice. This suggests that an afferent system can develop a normal organization despite having ectopic targets.
Visual system of the channel catfish (Ictalurus punctatus): III. Fiber order in the optic nerve and optic tract
Authors: Dunn‐Meynell A. A. , Sharma S. C. 
Published: January 2005

AbstractIn channel catfish the ganglion cell axons leave the retina via a ring of approximately 13 separate optic papillae. Each papilla serves an area of retina extending from the central zone of the retina to the periphery. Papillae located at a dorsal position in the ring serve exclusively dorsal retina. Ventrally located papillae, however, have an exaggerated peripheral retinal representation, so that they serve mostly ventral retina but also some areas of peripheral retina dorsal to the nasal and temporal poles. The ganglion cell axon bundles departing from the retina via individual papillae were labelled with horseradish peroxidase, and sections of the optic pathway were examined to reveal the topographic organization of the fibers. The topographic order of the optic nerve was dissimilar to that of cichlids and goldfish. Fibers from individual papillae remained together throughout the optic nerve. Close to the optic nerve head, the papillae were arranged as a continuum around the U‐shaped optic nerve, without the discontinuity in the representation of the ventral retina seen in other fish. Fibers associated with the dorsal papillae were located at the tip of the caudolateral arm of the U, and fibers from ventral papillae were on the rostromedial arm. Fibers from nasally and temporally located papillae were found on the base of the U. By the level of the optic chiasm the U shape had flattened out but retained the relative ordering of the papillae. Rotation of the nerve as it became the optic tract brought the representation of the ventral papillae to the dorsal pole of the tract, and the dorsal papillae to the ventral tract. It was only in the optic tract that rearrangement of fibers became apparent. As described above, the axons of some ganglion cells in dorsal, peripheral retina left the retina and travelled through the optic nerve with axons from extreme ventral retina. In the optic tract, these dorsal fibers joined the main body of fibers from the dorsal retina. The significance of these observations for theories of fiber rearrangement is discussed.