bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determinants of cell shape and orientation: A comparative Golgi analysis of cell‐axon interrelationships in the developing neocortex of normal and reeler mice
Authors: Lord M. C. Pinto , Caviness V. S. 
Published: January 2005

AbstractPatterns of dendritic development in the neocortex of normal and reeler E15‐17 mouse embryos are studied in Golgi impregnations. Interactions between dendrites and axon‐rich strata appear to be critical determinants of dendritic morphology in both genotypes. Firstly, axon‐dendrite proximity appears to stimulate dendritic sprouting, elongation and branching. Secondly, the position of the axon‐rich strata with respect to the differentiating cell appears to determine the direction of dendritic growth and thereby the ultimate configuration of the dendritic arbor. With regard to specific cell configuration, a multipolar form is generated when the cell is embedded in an axon‐rich zone. A monopolar or bipolar configuration is achieved when the cell lies in the axon‐poor cortical plate and addresses an axon‐rich stratum with one or both radially extended migratory processes. Such variations in the configuration of neurons with polar dendritic systems may be observed uniquely in the mutant cortex be cause axon‐rich zones are stratified anomalously at multiple levels in the cortical plate. As a consequence, polar dendritic systems develop from either the superior, the inferior or both somatic poles of postmigratory cells. Pyramidal cells may, therefore, develop a normal upright or an abnormal “upside‐down” disposition. Regardless of the orientation of the polar dendritic system, the axon emerges from the inferior aspect of the cell suggesting that there has been no rotation of the original migratory axis of the cell.
Visual thalamocortical connections in sheep studied by means of the retrograde transport of Horseradish‐Peroxidase
Authors: Karamanlidis A. N. , Saigal R. P. , Giolli R. A. , Mangana O. , Michaloudi H. 
Published: January 2005

AbstractIn order to study the visual thalamocortical connections in the sheep, horseradish peroxidase (0.3‐0.5 μ1 of a 30% solution) has been injected in the gyri marginalis, ectomarginalis medius pars medialis, ectomarginalis medius pars lateralis and ectosylvius caudalis. The results show that: (1) the dorsal lateral geniculate nucleus (LGNd) projects to the former three gyri. Dorsal parts of the LGNd project to caudal areas, whereas its ventral parts project to rostral areas of these gyri; medial parts of the LGNd project to the gyrus ectomarginalis medius pars lateralis, while lateral parts project to the gyrus marginalis; (2) the medial interlaminar nucleus (MIN) or pars geniculata pulvinaris of Rose ('42b) projects to the caudal part of the gyrus marginalis and to the gyrus ectomarginalis medius pars lateralis; (3) the pulvinar proper of Rose (PUL) projects to the caudal part of the gyrus ectosylvius caudalis whereas the rostral part of this gyrus receives input from the medial geniculate body.In relation to Rose's cytoarchitectonic study of the cortex of sheep (1942a) the present study has shown that the LGNd projects to both the area striata (gyrus marginalis + gyrus ectomarginalis medius pars medialis) and area occipitalis (gyrus ectomarginalis medius pars lateralis) of Rose, that the gyrus marginalis and the area occipitalis receive a second projection (from the MIN), and that the PUL projects beyond the area occipitalis to the area parietalis of Rose.
The retinothalamic pathways in Siamese cats
Authors: Cooper Michael Lee , Pettigrew John D. 
Published: January 2005

AbstractBy injecting one lateral geniculate nucleus with large amounts of horseradish peroxidase (HRP), we have determined the retinal distributions of contra‐ and ipsilaterally projecting retinothalamic ganglion cells in the Siamese cat. In accord with the data of others, we observe that large numbers of temporal ganglion cells, which normally send axons ipsilaterally, instead misproject to the contralateral thalamus. However, in contrast to the expectations raised by previous work, we do not find the Siamese defect to be a simple 20° shift of the naso‐temporal decussation line. Rather, there is intermingling of the crossed and uncrossed retinothalamic populations in the temporal retina, with a gradual increase in the proportion of ipsilaterally projecting ganglion cells as one moves temporally. Thus, the Siamese abnormality represents not only a temporal displacement of the retinothalamic decussation line, but also a smearing of the normally rather sharp division between regions of ipsilateral and contralateral projection.Cell size measurements and anterograde transport of H3‐proline confirm the HRP finding and suggest differential effects of the Siamese abnormality according to ganglion cell class. In particular, it appears that the large ganglion cells tend to misproject to a greater degree than the rest of the retinothalamic population.
The striate projection zone in the superior temporal sulcus of Macaca mulatta: Location and topographic organization
Authors: Ungerleider Leslie G. , Mishkin Mortimer 
Published: January 2005

AbstractIn the rhesus monkey, the caudal portion of the superior temporal sulcus (STS) receives a direct projection from lateral striate cortex, the striate area representing central vision. The present study was undertaken to determine whether STS also receives a direct projection from areas of striate cortex representing peripheral vision, with the intent of defining the entire striate projection zone in STS as well as providing information regarding a possible topographic organization within this secondary visual area. A series of five rhesus monkeys was prepared with unilateral lesions of lateral, posterior, or medial striate cortex, such that, collectively, the lesions in the series included all of striate cortex with little or no invasion of prestriate cortex. The monkeys were sacrificed seven days after surgery and their brains were processed by the Fink‐Heimer procedure. An analysis of the distribution of terminal degeneration within STS indicated: (1) All areas of striate cortex project to a restricted region along the caudal portion of STS. The ventral limit of this region can be demarcated by an imaginary line connecting the ventral tips of the lunate and intraparietal sulci; from this limit the region extends dorsocaudally for approximately 12 mm to the point at which STS frequently bifurcates, sending one spur forward into the inferior parietal lobule. (2) Within this portion of STS there is an orderly mapping of the visual field; progression from central vision to the far periphery is represented by a progression down the posterior bank of STS and continuing along the entire floor, or insula‐like portion, of the sulcus. (3) Projections from striate cortex to STS terminate predominantly in layer IV and the deep part of layer III. (4) There is a distinctive pattern of myelination contained within the striate projection zone of STS. These anatomical findings concerning the striate projection zone of STS. in the rhesus monkey are remarkably similar to those that have been described for the middle temporal visual area (MT) in New World monkeys, and thus support earlier proposals that the two areas are homologous.
Projections of the nucleus of the basal optic root in the pigeon: An autoradiographic and horseradish peroxidase study
Authors: Brecha Nicholas , Karten H. J. , Hunt S. P. 
Published: January 2005

AbstractThe efferent projections of the nBOR complex, have been studied with both anterograde autoradiographic and retrograde horseradish peroxidase (HRP) techniques. The nBOR complex includes three distinct subdivisions: the nucleus of the basal optic root (nBOR), the nBOR pars dorsalis (nBORd) and the nBOR pars lateralis (nBORl).Unilateral injections of 3H‐leucine or 3H‐proline/3H‐leucine mixtures into the nBOR complex have demonstrated prominent bilateral projections upon (1) the vestibulocerebellum, (2) the inferior olivary complex, (3) the oculomotor nuclear complex, (4) the nucleus interstitialis, contralateral projections upon (5) the contralateral nBOR complex and ipsilateral projections upon (6) a pretectal nucleus, the nucleus lentiformis mesencephali, pars magnocellularis.Unilateral injections of HRP confined to folia IXc, d and paraflocculus of the cerebellum, the contralateral nBOR complex or the nucleus lentiformis mesencephali resulted in retrograde labeling of predominantly medium and large size cells within the entire nBOR complex. Unilateral injections of HRP within the inferior olive resulted in retrograde labeling of small, spindle‐shaped cells within nBOR and nBORd. Unilateral injections of the oculomotor complex which included the trochlear nucleus resulted in retrograde labeling of small cells within the ipsilateral nBORd and predominantly medium and large cells in the contralateral nBOR.The displaced ganglion cells of the retina give rise to a prominent and distinct projection upon the nBOR complex (Karten et al., '77). The nBOR complex in turn projects upon the oculomotor nuclear complex, the nucleus interstitialis and the vestibulocerebellum, regions which have been implicated in oculomotor function. These findings strongly suggest that the displaced ganglion cells and the accessory optic system have a major influence upon oculomotor reflexes including eye and head movements.
Ontogeny of the retina and optic nerve in Xenopus laevis. II. Ontogeny of the optic fiber pattern in the retina
Authors: Grant Philip , Rubin Eric 
Published: January 2005

AbstractThe ontogeny of optic fiber patterns within the Xenopus laevis retina has been studied in silver‐stained serial sections and whole mounts. Ganglion cell axons (“pioneers”) appear much earlier than previously recognized, at Nieuwkoop‐Faber ('56) Stage 28. Fibers fasciculate into bundles as they arise in the retina and reach the chiasma by NF Stage 32. Because the retina grows in rings at its margins, ganglion cell axons differentiate at the periphery and join the nearest fiber bundles (fascicles) to reach the optical disc. A radial fascicle pattern develops by Stage X (Grant et al., '80) within the optic fiber layer of the retina and acts as a template of pathways that lead all later appearing fibers out of the retina. Since the retina grows asymmetrically along its dorso‐ventral axis, the fascicle pattern develops asymmetrically, with dorsal quadrant fascicles forming an arcuate pattern in contrast to shorter, thicker ventral quadrant fascicles.The growth pattern of the retina and the “principle” of fiber following suggest that ‘positional information’ is acquired by ganglion cells according to a system of polar coordinates (MacDonald, '77). A radial distance “r” from the center is determined temporally by ganglion cell birthday and an angular value “TH” is given by the angular position of the fascicle followed by its axons to the optical disc. Wedges of ganglion cells send their axons into a common fascicle which retains its integrity as it leaves the retina at the optic disc. This pattern of optic fiber development suggests a model for retino‐topic ordering of the optic fiber projection in Xenopus, with the fascicle acting as the “pattern‐forming unit of connectivity.”.
Cells of origin of the afferent fibers to the median eminence in the rat
Authors: Wiegand S. J. , Price J. L. 
Published: January 2005

AbstractThe cell bodies of origin of axons terminating in the median eminence have been identified by retrograde axonal transport of horseradish peroxidase (HRP) or 125I‐wheat germ agglutinin (WGA). The tracers were injected into the median eminence by pressure and under direct visual control, using a ventral surgical approach. The retrogradely labeled cells are exclusively located within the hypothalamus. The most heavily labeled cells are parvocellular neurons in the arcuate nucleus, the periventricular area, the medial part of the paraventricular nucleus, and the rostral paraventricular nucleus; a few cells are also located in the rostral part of the preoptic area immediately lateral and dorsal to the organum vasculosum of the lamina terminalis (OVLT). Less heavily labeled cells are found in the magnocellular neurosecretory nuclei, including the lateral parts of the paraventricular and rostral paraventricular nuclei, the supraoptic nucleus, and the accessory magnocellular nuclei.Retrogradely labeled cells are not found in the ventromedial hypothalamic nucleus, except for a few lightly labeled cells in the posterior division of the nucleus. However, if the injected tracer spreads into the arcuate nucleus, labeled cells are present throughout the ventromedial nucleus. Labeled cells are not found in other parts of the hypothalamus, including lateral and posterior portions of the preoptic area, the anterior hypothalamic area, and the suprachiasmatic nucleus, or in catecholaminergic cell groups of the midbrain, pons, and medulla.Control injections of HRP into the posterior pituitary and the ventromedial nucleus produce patterns of cell labeling which are very distinct from that seen with injections into the median eminence. Following injections into the posterior pituitary, the cells of the magnocellular neurosecretory nuclei are all heavily labeled, but small cells in the parvocellular neuronal groups are not labeled. Direct injections into the ventromedial nucleus resulted in labeled cells in widespread parts of the hypothalamus, as well as in the bed nucleus of the stria terminalis and the lateral septum, in parts of the amygdaloid complex and the subiculum, and in several cell groups in the midbrain, pons, and medulla.
Afferents to oculomotor nuclei from area “y” in Macaca mulatta: An anterograde degeneration study
Authors: Stanton Gregory B. 
Published: January 2005

AbstractElectrolytic lesions were placed in the dentate and interpositus nuclei of the monkey M. mulatta and the resulting anterograde degeneration was stained with the Wiitanen or Nauta‐Laidlaw techniques. Two of 19 lesions produced preterminal degeneration in the oculomotor nuclei. In both cases the lesions also damaged vestibular area “y” subjacent to the rostral pole of the dentate nucleus. The course and terminal distribution of anterograde degeneration to the oculomotor nuclei was the same in both cases. Degenerating fibers were found in lateral parts of the ipsilateral MLF, and preterminal degeneration was found in the ipsilateral abducens and trochlear nuclei and the dorsal subdivision of the oculomotor nucleus. Degenerating fibers were also traced from the crossed brachium conjunctivum to the contralateral paramedian subdivision of the oculomotor nucleus. These fibers appeared to course in dorsomedial parts of the brachium. Lesions of the dentate and interpositus nuclei which did not damage area “y” produced no anterograde axonal degeneration in the MLF or the oculomotor nerve nuclei. The results are discussed with regard to previous reports of cerebello‐oculomotor fibers originating in the dentate and interpositus nuclei. The results suggest that area “y”, rather than the cerebellar nuclei, projects principally to oculomotor neurons that control vertical eye movements.
Interactions among lumbar motoneurons on opposite sides of the frog spinal cord: Morphological and electrophysiological studies
Authors: Erulkar S. D. , Soller R. William 
Published: January 2005

AbstractLight and electron microscopy have been used to study the projections of dendrites from motoneurons in lumbar segments of the spinal cord of the frog following administration of horseradish peroxidase to cut ventral roots. Processes originating from motoneurons crossed to the opposite side of the spinal cord via the anterior commissure and made contact with dendrites and motoneuronal somata. Typically, in segments 6 to 8 the crossing dendrites showed irregular enlargements in diameter.Electrophysiological recordings were obtained both extracellularly from ventral roots and intracellularly from motoneuronal somata. In Ringer's solution containing 1 mM calcium, stimulation of a lumbar ventral root elicited population responses with early and late components in the ventral root of the opposite side of the same segment. Only the early, short latency component remained in calcium deficient Ringer's solution. In calcium‐containing Ringer's solution, intracellular recording from an antidromically activated motoneuron showed an action potential with a short latency; this response was followed by excitatory postsynaptic potentials (epsps) from which action potentials could be generated. Contralateral ventral root stimulation also elicited in the same motoneuron a short latency action potential that was rarely followed by epsps. The short latency responses, that were elicited by stimulation of ventral roots of either side persisted in calcium‐deficient Ringer's solution, but the epsps were abolished. Contralaterally elicited short latency responses were eliminated by section of the anterior commissure.We believe that electrically mediated crossed interactions among lumbar motoneurons may serve as a means of coordinating muscle groups of opposite sides that are used in movements that require bilateral synchronization, such as jumping and swimming.
Supraependymal macrophages of third ventricle of hamster: Morphological, functional and histochemical characterization in situ and in culture
Authors: Bleier Ruth , Albrecht Ralph 
Published: January 2005

AbstractSupraependymal cells (SECs) of the young hamster's third ventricle have been examined by scanning and transmission electron microscopy. Of special interest were cells with the surface morphology and ultrastructure of macrophages, which were found in largest numbers in 12–15‐day‐old females and males. In the ciliated areas SECs are generally smooth and rounded; in nonciliated areas, they frequently have surface ruffles, blebs and microprocesses. SECs were frequently seen to be dividing or fusing. The macrophage‐like cells are characterized by prominent Golgi zones and numerous large vacuoles, and frequently contain inclusions in their cytoplasm which resemble intraventricular cell processes, cytoplasmic protrusions from ependymal cells and cellular debris. We have demonstrated that supraependymal macrophage‐like cells phagocytose latex beads injected into the ventricles of the brain.Supraependymal cells from 12‐day‐old hamsters were grown in tissue culture. Phagocytic, cytochemical and surface ultrastructural studies were then done sequentially on the same population of cells. These studies revealed the cells to be actively phagocytic as well as strongly esterase positive and peroxidase negative, consistent with their classification in the macrophage/monocyte category. The surface ruffles, ridges and microprocesses were also characteristic of the SECs seen in situ with scanning electron microscopy and of the macrophages cultured from the peritoneum and peripheral blood of the same hamsters.On the basis of cellular morphology, cytochemical staining characteristics and functional response to exposure to foreign particles both in situ and in cell culture, we have demonstrated that supraependymal cells of the third ventricle of the hamster are phagocytes that resemble cells of the macrophage/monocyte line. It is suggested that they constitute a resident macrophage system of the ventricles of the brain.
Organization of the motoneurons innervating the pelvic muscles of the male rat
Authors: Schrøder Henrik Daa 
Published: January 2005

AbstractThe cytoarchitecture of the motoneuron pool of the male rat was studied at the lumbo‐sacral transition area, particularly in L6. In the latter segment a dorso‐medial (DM), ventral (V), dorso‐lateral (DL), and retrodorso‐lateral group (RDL) could be defined. The DL group was associated with a prominent longitudinal dendrite bundle and the DM group with smaller transverse bundles. Morever, close soma‐somatic apposition was found between neurons in these columns.Because L6gives rise to n. pudendus and contributes to n. ischiadicus, horseradish peroxidase (HRP) was applied to the cut n. ischiadicus and in other experiments injected into the pelvic muscles. Neurons in RDL were labeled following exposure of n. ischiadicus to HRP. Injections in m. levator ani resulted in labeled neurons in the V group, mainly below L6. Injections in m. sphincter urethrae resulted in labeled neurons in the DL group as well as neurons immediately cranial to this column. Musculus ischiocavernosus injections resulted in transport of HRP to neurons in the DL group, primarily in its medial part, and to more cranially located neurons. In addition, some neurons in the V group in L6were labeled. Following injections in m. bulbocavernosus and m. sphincter ani, labeled neurons were found primarily in the DM group, and to a lesser extent in the V group.Histochemical investigations with staining methods for the localization of acetyl cholinesterase (AChE) and heavy metals (the Timm method) demonstrated that part of the neuropil of DL and of DM were different from the rest of the motoneuron neuropil. In the DL group the area with the diverging staining patterns corresponded to the region of the dendrite bundle. The experimental data indicated and the ultrastructural studies demonstrated that the histochemical differences could be correlated with differences in the composition of the populations of boutons.The comparison of the cytoarchitectural and histochemical data with the results obtained by the aid of the retrograde HRP tracing technique established that mm. sphincter urethrae, ischiocavernosus, bulbocavernosus, and sphincter ani were each innervated by two populations of neurons that were situated in separate areas which had different histochemical properties, and which thus probably have different compositions of their afferent inputs.The daulity in the motoneuron pool that innervates the pelvic muscles might be a reflection of the dual influence on these muscles. As all other striated muscles the pelvic muscles are under voluntary control. However, they are also tightly linked to the function of the pelvic viscera and thus under influence of the autonomic nervous system.
Reciprocal synapses between hair cells and first order afferent dendrites in the crista ampullaris of the bullfrog
Authors: Dunn Robert F. 
Published: January 2005

AbstractReciprocal synapses were found between afferent dendrites and hair cells of the crista ampullaris in the vestibular system of the bullfrog. The reciprocal synapse consisted of two components forming a dual synaptic complex between a single hair cell and a single dendritic process such that the receptor cell was both presynaptic and postsynaptic to the afferent dendrite. The first component, a typical afferent synaptic complex, consisted of a synaptic sphere surrounded by a single layer of clear vesicles, and was located within the hair cell. In addition, 3–4 arciform structures were located between the sphere and the plasma membrane of the hair cell. The second component of the reciprocal synapse, located approximately 1.5 μm from the first, was recognized by a localized accumulation of clear membrane vesicles within the neuronal process and a short membrane profile within the cytoplasm of the adjacent hair cell. Additional characteristic features included continuity of the arciform structures with the plasma membrane of the hair cell, and within the neuronal process, a greatly reduced number of vesicles when compared with the efferent axonal terminal. This latter was important in distinguishing a first‐order afferent dendritic process from an efferent neuronal process. The possible functional significance of these reciprocal synapses has been discussed in terms of the two components having an opposite effect on the membrane polarization of the hair cell.