bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cortical cells projecting to the dorsal column nuclei of cats. An anatomical study with the horseradish peroxidase technique
Authors: Weisberg J. A. , Rustioni A. 
Published: January 2005

AbstractThe retrograde transport of horseradish peroxidase (HRP) has been used to label cortical neurons which give origin to descending projections to the dorsal column nuclei (DCN) in kittens and adult cats. HRP was injected unilaterally or bilaterally into the dorsal medulla at, or rostral to, the level of the obex, and, in most cases, retrogradely transported HRP was visualized in cortical neurons by incubation of serial 40 μm coronal or sagittal frozen sections. In the remaining cases, 1 mm coronal or sagittal slabs through the anterior part of the cerebral hemisphere were cut and incubated en bloc, and embedded in celloidin for sectioning (40 μm).HRP‐positive neurons identifiable as the source of cortical projections to the DCN were layer V pyramidal cells whose largest diameter ranged from 20 to 45 μm: no “giant” cells were labelled. The cells appeared concentrated in the fore‐and hindlimb regions of the sensorimotor cortex and, to a lesser extent, in the second somatosensory area contralateral to the injected side. Labelled neurons were especially numerous in the upper bank of the cruciate sulcus and in the medial wall of the posterior sigmoid gyrus which respectively form parts of areas 4 and 3a (Hassler and Muhs‐Clement, '64). The number of labelled neurons progressively diminished in the first somatosensory area proper (areas 3b, 1 and 2). Ipsilaterally, fewer labelled neurons were present, mainly in areas 4 and 3a.These results are in general agreement with previous anatomical and electrophysiological studies. It is suggested that previous results based upon lesions or electrical stimulation of the cerebral cortex in cats have failed to reveal adequately the cortical regions containing the bulk of the cells projecting to the DCN, since these regions have escaped selective experimental manipulation due to their relative inaccessibility.
Properties of ganglion cells in the visual streak of the cat's retina
Authors: Rowe Michael H. , Stone Jonathan 
Published: January 2005

AbstractThe properties of ganglion cells in the visual streak of the cat's retina have been investigated. Evidence is presented that the streak is formed principally, but not entirely, by a concentration of small‐bodied ganglion cells with the receptive field properties and slow‐conducting axons typical of W‐cells.
The development of the cerebellar cortex of the syrian hamster, Mesocricetus auratus. Foliation, cytoarchitectonic, golgi, and electron microscopic studies
Authors: Oster‐Granite Mary Lou , Herndon Robert M. 
Published: January 2005

AbstractAlthough a number of investigations of abnormalities of cerebellar development have been carried out in the hamster, no detailed Golgi or ultrastructural studies of cerebellar development in this species have been reported. This report describes the development of the hamster cerebellar cortex from birth (day 0) through postnatal day 78, as studied by light, Golgi, and electron microscopic methods. Foliation patterns correlate with the expansion of the cerebellar layers and of total cerebellar area. Cytologic and morphologic development of the major cerebellar cell types–Purkinje, Golgi, basket, stellate, granule, and Bergmann glial cells–correlate with those of other species, such as the rat and mouse. Electron microscopic observations at selected developmental ages allow identification and classification of synapses in the early postnatal hamster. Parallel fiber and climbing fiber synapses are already present at birth. Although synaptogenesis probably continues through the first two postnatal months, all major cell types have developed initial synapses by postnatal day 6, at a time when little cellular maturation has occurred. By using gestational rather than natal age, close developmental correlations between hamsters and rat and mouse are possible. Since the gestational period of the hamster is only 16 days, the hamster cerebellum is less mature at birth than that of either the rat or mouse. Thus, the hamster is a convenient animal in which to investigate the effects of various procedures on early cerebellar development.
Evidence that at least some of the motor nerve cells that die during development have first made peripheral connections
Authors: Prestige M. C. 
Published: January 2005

AbstractThe paper sets out to determine whether the spinal motoneurons that die during the normal development of Xenopus tadpoles have been peripherally connected before death. The numbers of cells in the control ventral horns were compared with the numbers remaining after early (stage 50 or 52/53) amputation of the limb bud. Up to stage 52, there was no difference between the two sides, but thereafter the numbers on the amputated side fell away until at stage 57 none were left. Thus, as neurons mature, they become dependent for survival on contacting the limb. During this time, there was no difference between amputees and controls in the numbers of mitoses in that part of the ventricular layer that gives rise to ventral horn cells, indicating no change in proliferation. Thus, the numbers of ventral horn cells remaining after early amputation is a measure of the numbers of cells in the normal animal that are still independent of the limb (Phase I cells) and hence by subtraction, the other cells (post‐Phase I cells) are those that only survive by virtue of having contacted the limb. A graph of numbers of post‐Phase I cells shows a peak at stage 54 and thereafter declines as metamorphosis approaches. This is interpreted to indicate that a number of cells that survive at stage 54 by reason of peripheral contacts or connections in the limb subsequently themselves die, that is, that at least some of the cells that die during normal development have previously made contacts within the limb.
An electron microscope study of motoneurones and interneurones in the cat abducens nucleus identified by retrograde intraaxonal transport of horseradish peroxidase
Authors: Spencer Robert F. , Sterling Peter 
Published: January 2005

AbstractAbducens motoneurones innervating the lateral rectus muscle and abducens interneurones projecting to the oculomotor nucleus have been studied in the cat by light and electron microscopy following labelling with horseradish peroxidase. Motoneurones ranged from 15–60 μm in diameter and typically contained circular nuclei with smooth or slightly irregular nuclear membranes and extensive cisternae of granular endoplasmic reticulum. Interneurones ranged from 25–50 μm in diameter and comprised two cytologically distinct cell types. One type was fusiform in profile and contained nuclei with fluted or deeply invaginated nuclear membranes and poorly developed granular endoplasmic reticulum. The other interneurone type resembled the motoneurones cytologically, having multipolar or circular profiles, smooth or slightly irregular nuclear membranes, and well developed cisternae of granular endoplasmic reticulum.The densities with which boutons were distributed on the somata of motoneurones and interneurones were similar, as were the ratios of boutons containing spheroidal or flattened synaptic vesicles. Motoneurones varied significantly in the density with which boutons were distributed on their somata, and had greater densities on their dendrites than on their somata. Density was, furthermore, not correlated with motoneurone soma diameter. The proportion of spheroidal or flattened vesicle boutons on the somata of motoneurones was almost equal, with comparatively little variation between individual motoneurones. Motoneurone dendrites, however, with the exception of lateral dendrites, had a relatively higher proportion of boutons containing spheroidal synaptic vesicles. The lateral dendrites, which extend toward the medial vestibular nucleus, a known source of inhibitory afferents to the abducens motoneurones, had a higher proportion of boutons containing flattened vesicles.The results indicate that abducens motoneurones and interneurones cannot be distinguished by any simple morphological criteria. The somadendritic distribution of boutons on motoneurones appears to be governed by certain broad rules.
Distribution of commissural afferents to the hippocampus of the rabbit
Authors: Hjorth‐Simonsen A. 
Published: January 2005

AbstractThe commissural connections of the hippocampus (fascia dentata and Ammon's horn) were investigated in the rabbit using a Fink‐Heimer silver impregnation method after the transection of either or both hippocampal commissures. In some cases additional sections were processed either with a histochemical method for acetyl cholinesterase or with the Timm‐Haug sulfide silver method.The fibers to the fascia dentata arrive through the ventral commissure and terminate in a juxtagranular zone that corresponds to a relatively pale zone in acetyl cholinesterase preparations and to a dark zone in Timm‐Haug sulfide silver preparations. The degeneration is more dense in the middle of the Ushaped cross‐sectional profile of the fascia dentata than at the edges. This is particularly evident in the ventral portion of the fascia dentata. There is no evidence of commissural terminals in the layer of polymorphic cells. The commissural fibers to the Ammon's horn pass through both commissures. The fibers in the dorsal commissure terminate in the strata radiatum, oriens and pyramidale at their transition to the subiculum, in the septal part of the Ammon's horn. The molecular layer contains relatively little degeneration after transection of the dorsal commissure with the exception of the crossed entorhinal efferents to the rostral part. Fibers from the ventral commissure terminate in both the stratum oriens and the stratum radiatum. The degeneration in the stratum oriens is dense through the full extent of the layer, while that in the stratum radiatum is maximal in the regio inferior near the fimbria and less dense close to the fascia dentata and in the regio superior, with the exception of the antero‐rostral extreme of the latter. The density of degeneration in the stratum radiatum diminishes in the postero‐ventral direction except for degeneration at the subicular and dentate ends of the layer.Evidence is presented for a powerful ipsilateral longitudinal association path terminating in the stratum radiatum of the regio inferior and in a minor adjacent portion of the dentate commissural zone.
The inferior olivary complex of marsupials
Authors: Watson Charles R. R. , Herron Paul 
Published: January 2005

AbstractThe inferior olivary complex (IOC) of marsupials was investigated to determine if correspondence exists between the IOC of marsupials and the IOC of eutherian mammals. We examined serial sections of the IOC of members of the eight major marsupial families: Didelphidae (Didelphis virginana, Philander opossum, Marmosa murina, and Caluromys sp.), Caenolestidae (Caenolestes obscurus and Lestoros inca), Dasyuridae (Antechinus flavipes, Dasyurus viverrinus and Sarcophilus harrisii), Peramelidae (Isodon obesulus and Perameles nasuta), Phalangeridae (Trichosurus vulpecula and Pseudocheirus peregrinus), Petauridae (Schoinobates volans and Petaurus breviceps), Vombatidae (Vombatus ursinus) and Macropodidae (Potorous tridactylus, Setonix brachyurus, Macropus eugenii and Macropus rufus).Evidence is presented that the principal nucleus (PIO) and dorsal nucleus (DIO) of the marsupial IOC are directly comparable to nuclei in eutherians. Nauta degeneration studies on the pattern of termination of spinal and rubral afferents in Trichosurus vulpecula support arguments for homology between the PIO and DIO of marsupials and of eutherians. However the probable homologue of the eutherian medial nucleus (MIO) has certain features that are unique to marsupials; while it can be divided into the same subnuclei found in eutherians (subnuclei a, b, c and the cap of Kooy) most of the cells of the marsupial medial nucleus homologue are located lateral to the PIO. The few cells of the MIO homologue that lie medial to the PIO are connected in some marsupials to the main lateral portion by a sheet of cells that lies ventral to the PIO. For this reason we propose that the medial nucleus homologue be named the ventral nucleus (VIO) in marsupials. Because of the ventral position occupied by medial nucleus cells during development in both eutherian and marsupial mammals, the term VIO could also be properly applied to the eutherian MIO as well.
The cerebellum of the bullfrog tadpole (Rana catesbeiana)
Authors: Uray Nandor J. , Gona Amos G. 
Published: January 2005

AbstractThe cerebellum of the premetamorphic bullfrog tadpole differs from the cerebellum of other frog species in its morphology and maturational state. The cell mass beneath the floor of the lateral recess and bordering its lateral wall that has been reported to form the auricular lobe in other species is absent, the auricular lobe abutting the medial wall of the lateral recess instead and is continuous with the corpus cerebelli. The corpus cerebelli, although immature and yet to acquire an external granular layer, is already massive and displays an incipient molecular, Purkinje cell and granular layers.Cytodifferentiation in the auricular lobe and corpus cerebelli is similar, their constituent cells being in various stages of development. Fully mature cells are absent, but a small population of Purkinje cells and glia in the auricular lobe and along the marginal zone of the corpus cerebelli show advanced development. The orientation of these Purkinje cells is parallel to the pia and appears to approximate the course of the vestibulo‐lateral commissural fibers. In the ventral part of the corpus cerebelli, developing climbing fibers are present but Purkinje cells are poorly developed.
The role of superior colliculus in vision: Visual form discrimination in cats with superior colliculus ablations
Authors: Tunkl J. E. , Berkley M. A. 
Published: January 2005

AbstractThe rate of acquisition of visual form discriminations in cats with superior colliculus damage was measured in a testing apparatus requiring a minimal amount of stimulus localization in space. In animals with bilateral superior colliculus ablations, acquisition was impaired relative to acquisition in normal animals. In these animals, the extent of the lesion was related to the severity of the deficit. In split‐brain preparations with unilateral superior colliculus ablations, acquisition with the eye ipsilateral to the lesion was impaired relative to acquisition with eye contralateral to the lesion. The deficits observed did not depend upon damage to pretectum. The results support the conclusion that the superior colliculus participates in certain aspects of form vision.
Abnormal development of the suprachiasmatic nuclei of the hypothalamus in a strain of genetically anophthalmic mice
Authors: Silver Jerry 
Published: January 2005

AbstractIn the anophthalmic mutant of the mouse the optic primordia are “genetically enucleated” well before the usual emergence of retinal ganglion cell axons (Silver and Hughes, '74). In eyeless animals, a portion of the mediobasal hypothalamus and one of its constituent nuclear pairs, nucleus suprachiasmaticus (SCN), were markedly abnormal in the embryo and adult. It has been reported that the ventral portion of the SCN receives a substantial, direct retinal innervation (Moore and Lenn, '72) and that these nuclei may mediate several light‐induced hormonal and behavioral circadian rhythms (Stetson and Whitmyre, '76). During day 13 of mutant embryogenesis, just prior to the time of optic chiasm formation in normal animals, a large portion of ependyma and adjacent brain tissue herniated into the lumen of the would‐be suprachiasmatic region of the third ventricle. In 70% of the animals examined histologically during the latter phase of development and as adults, regulation occurred and the brains were largely comparable with those of controls. However, in the remaining mutant mice, the overall size of either, or sometimes both, SCN was much reduced. The basal (but not the apical) dendrited of SCN neurons failed to develop fully. Some basal dendrites normally invade the optic chiasm below. In several mutant animals one or the other SCN had greatly increased numbers of cells, while the contralateral one had diminished numbers. These observations suggest that regular formation of the suprachiasmatic region of the hypothalamus and especially the suprachiasmatic nuclei, may depend during development upon the presence of the eye or the subjacent optic axons.
Autoradiographic maps of regional brain glucose consumption in resting, awake rats using [14c] 2‐deoxyglucose
Authors: Schwartz William J. , Sharp Frank R. 
Published: January 2005

AbstractThe 2‐deoxy‐D‐[14C]‐glucose (2‐DG) autoradiographic method for determining regional brain glucose consumption has been applied successfully by a number of workers for mapping the alterations of brain glucose consumption which occur in association with experimental alterations of brain functional activity. This paper provides a framework for the interpretation of these and further studies by presenting: (1) the pattern of regional brain glucose consumption in the normal, resting, awake rat; (2) the anatomical identities of brain structures which on autoradiographs appear only as regional variations of optical density. For this purpose, a series of 2‐DG autoradiographs of coronal brain sections from an injected animal is compared with adjacent labeled Nissl sections.
Postnatal formation of non‐neuronal cells in the rat occipital cerebrum: An autoradiographic study of the time and space pattern of cell division
Authors: Mareš Vladislav , Brückner Gert 
Published: January 2005

AbstractRats of the BD III strain were injected with3H‐thymidine (5 μCi per g b. wt.) at postnatal day (PD) 1,3,7,12,16 and 21 and were killed at PD 22‐27 and 27 respectively. The number of cells synthesizing DNA in the visual cortex (areas 17, 18 and 18a) was detected by light microscope autoradiography. It was found that proliferation of non‐Neuronal cells of bothecto‐ (i.e., astrocytes and oligodendrocytes) andmeso‐dermalorigin (endothelial cells, microglia, pericytes, etc.) increases postnatally, reaching a peak at PD 3‐7. After a transient fall of the proliferation rate towards PD 12, another peak in the number of labeled cells was found at PD 16. In ectodermally derived glial cells the latter was evident in the deep cortical layers and the subcortical white matter; in mesodermally derived groups of cells the second peak was clearly evident in all gray matter layers as well as in the adjacent white matter.Another group of animals aged 1,3,7,12,16 and 21 days was injected with3H‐thymidine (5 μCi per g b. wt.) and the animals were killed two hours after the injection. It was shown that towards PD 3‐7 proliferation, of non‐neuronal cells increased in all layers of the hemispheric wall, including leptomeninges. At PD 16 the increase in cell division involved only germinative cells of the periventricular layer. Factors responsible for the cyclic course of proliferation of nonneuronal cells and its relationship to the process of tissue differentiation are not clear. Increased rate of formation ofectodermallyderived glial cells can be related to the (a) intensified growth of surface of nerve cells and vessels – since both must be encased in glial cells – and (b) to the formation of myelin. Changes in the production of non‐neuronal cells ofmesodermalorigin reflect most probably changes in the rate of vasculogenesis because of the high prevalence of endothelial cells in this cell group.
The projection of the opossum's visual field on the cerebral cortex
Authors: Sousa Aglai P. B. , Gattass R. , Oswaldo‐Cruz E. 
Published: January 2005

AbstractThe visual cortex of the opossum was studied by means of evoked potential and multi‐unit recordings, and a map of the visual field in VI was constructed: Evoked responses were observed in regions extending beyond the boundaries of striate cortex. Different patterns of response were obtained depending on the cortical region undergoing exploration: in a posteromedial region, coincident with striate area, complex waveforms were obtained, contrasting with the simpler forms observed in a region localized anterolaterally. VI, which corresponds to cytoarchitectonic area 17, has a topography of projections similar to that found in other mammals: the upper visual field represented posteriorly, the temporal field represented medially, the lower field represented anteriorly and the nasal part laterally. A large proportion of VI is devoted to the region of binocular representation, which covers approximately100° at the level of the horizontal meridian. The cortical representation of the vertical meridian extends to approximately 60°above and below the center of gaze, suggesting that the cortical representation of the visual field is more restricted than the visual field available to the contralateral hemiretina. Our results suggest that the extreme periphery of the field is not represented in VI. In its lateral border the projection does not end at the vertical meridian, it extends 5° into the ipsilateral hemififield of vision, so that approximately 10° of visual field is represented in both hemispheres. There is a reversal of representation along the lateral border of VI, in a region which coincides with the cytoarchitectonic boundaries of striate and peristriate areas, suggesting the existence of at least a second representation of the visual field in the neocortex of the opossum, corresponding to VII of other animals.The magnification factor in VI varied from 7°/mm observed at the cortical representation of the center of gaze, to 30°/mm at the extreme periphery of the field, along the horizontal meridian. A comparable decrease was also observed along the vertical meridian, towards the upper and lower limits of the visual field.
Spinal projection to the dorsolateral nucleus of the caudal basilar pons in the cat
Authors: Rüegg D. G. , Eldred E. , Wiesendanger M. 
Published: January 2005

AbstractIn the cat, a spinal projection to a restricted area of the basilar pontine grey has been revealed with use of an anterograde degeneration technique (Fink‐Heimer). The area was ipsilateral to the spinal lesion, restricted to the far caudal limit of the pons, and included the dorsal and the dorsolateral subdivisions of the pontine nuclei (PN). Comparisons following high cervical, midthoracic and upper lumbar spinal lesions did not reveal any somatotopic organization. Only a few spinopontine fibers had origins below segmental level L4. Lesions of various quadrants of the cord indicated that the spinopontine fibers ascendede through the dorsolateral funiculus, and not through either the dorsal or the verntal funiculi. Comparison with the degeneration effects of cerebral cortical lesions showed that the spinal projection from the first sensorimotor and second somatosensory cortices. In the rat no comparable spinopontine projection was found.It is suggested that the spinopontine pathway migh forward information to the cerebellum from visceral sensory receptors or perhaps from pools of spinal interneurons.