bluuebunny/crossref_metadata_2025_split huggingface dataset:
The cell masses in the brain stem of the turtle Testudo hermanni; α a topographical and topological analysis
Authors: Cruce William L. R. , Nieuwenhuys Rudolf 
Published: January 2005

AbstractThe ventricular sulcal pattern and the cytoarchitectonic organization of the brain stem of the turtle Testudo hermanni have been studied in transversely cut, Nissl stained serial sections. Four longitudinal sulci, the sulcus medianus inferior, the sulcus intermedius ventralis, the sulcus limitans and the sulcus medianus superior could be distinguished. With the aid of the usual cytoarchitectonic criteria 54 cell groups have been delimited; 12 of these are primary efferent or motor nuclei, 13 are primary afferent or sensory centers; 10 of the nuclei distinguished are considered as belonging to the reticular formation. The remaining 19 cell masses can be indicated as “relay” nuclei. In order to provide a basis for experimental hodological work the topographical position of the nuclei is illustrated in photomicrographs of representative levels and in graphical reconstructions.In order to elucidate the morphological pattern of the cell masses and their relationship to the ventricular sulci the brain stem was subjected to a topological analysis. Essentially this method requires that (1) the cell masses are projected upon the ventricular surface and that (2) this surface, with its sulci marked on it and with the outlines of the subjacent cell masses projected upon it, is flattened out. This analysis yielded the following results: The sulcus limitans extends throughout the rhombencephalon, dividing this brain part into a basal plate and an alar plate. In the basal plate the sulcus intermedius ventralis marks the boundary between an area ventralis and an area intermedioventralis containing, respectively, the somatic motor nuclei of primary and higher order, and the visceral motor centers. Yet the terms somatic motor zone and visceral motor zone are not applicable to these two areas as a whole since both contain a number of non‐motor centers. Thus the intermedioventral zone harbours two general somatic sensory centers, i.e., the spinal‐ and princeps nuclei of V. The medial parts of the tegmentum isthmi and of the tegmentum mesencephali contain somatic motor centers of primary and higher order, and thus may be considered rostral continuations of the rhombencephalic ventral zone. The rhombencephalic alar plate contains visceral sensory, general somatic sensory and special somatic sensory centers, but these do not show a simple ventrodorsal arrangement. A prominent feature is that the special somatic sensory nuclei of termination of VIII, the cerebellar nuclei, and a number of special somatic sensory centers of higher order together constitute a continuous zone which extends from the rhombencephalic alar plate, via the isthmus into the lateral part of the tegmentum mesencephali. In the isthmus region the sulcus limitans does not mark the ventral boundary of this zone, but rather passes over its middle.
Time of neuron origin in the anterior olfactory nucleus and nucleus of the lateral olfactory tract of the mouse: An autoradiographic study
Authors: Creps Elaine S. 
Published: January 2005

AbstractTime of neuron origin in the anterior olfactory nucleus (AO) and nucleus of the lateral olfactory tract (NTOL) was determined autoradiographically in adult mice which received tritiated thymidine once during development. Each subdivision of AO has an individualized period and pattern of neuron origin. All subdivisions contain neurons which arise on E11; but the medial, dorsal, and external subdivisions complete their complement by E18 whereas posterior and lateral neurons continue to arise through P1. No gradients along the caudorostral axis were discerned. Neurons of NTOL arise early (E10‐14), typical of large neurons and similar to those of the surrounding anterior amygdaloid area.
Efferent cortico‐cortical fiber connections of area 18 in the squirrel monkey (Saimiri)
Authors: Tigges J. , Spatz W. B. , Tigges M. 
Published: January 2005

AbstractAssociation fibers, degenerating as a result of laminar heat lesions in area 18 of Saimiri, were traced to their respective cortical terminal sites. A strong intrinsic fiber system connected the supragranular cell layers with the underlying layer V of area 18. In addition, the supragranular layers of area 18 projected ipsilaterally to area 17, the territory of area 19 and area MT in the posterior bank of the superior temporal sulcus. Sparse fibers were traced to the cortex in the intraparietal sulcus and to area 8. The projection upon area 17 was strictly topographical; the termination of these fibers was restricted to layer I of area 17. The projection upon area 18 also showed signs of a topographical organization, though less distinct. The evidence for the existence of Brodmann's classic area 19 or its possible replacement as suggested by Allman and coworkers is discussed.Callosal fibers terminated in a topographically organized manner in a strip of cortex posterior in area 18, i.e., the OBg of von Bonin, and in a strip of cortex probably in anterior area 18. A sparse projection connected area 18 with the contralateral area MT.
The cochlear nuclei of lizards
Authors: Miller Malcolm R. 
Published: January 2005

AbstractThe cochlear nuclei of 14 lizard species (eight families) were studied in normal animals and in a small series of animals with lesions of the posterior division of the eight nerve. The development of the cochlear nuclei is directly related to the length and complexity of the papilla basilaris. The best development of basilar papillae and cochlear nuclei is found in teiid and gekkonid lizards, and an intermediate grade of development in scincid, lacertid, and anguid lizards. A lesser degree of development occurs in the igunids, and practically no cochlear nuclei differentiation is observed in chameleo.Two well defined cochlear nuclei are found in most lizard families: nucleus angularis (NA) and nucleus magnocellularis medialis (NMM). NA is located in the cephalic third of the acoustic tubercle and contains variably sized darkly staining cells. NMM is the most caudally located nuclear group and is characterized by regularly round to ovoid cells. The development of NMM is more closely related to papilla basilaris length and complexity than is NA.Two less well defined cochlear nuclei are also thought to be present. In the region between NA and NMM is a sparsely cell‐populated area, nucleus magno‐cellularis lateralis (NMM), which consists of a variety of small, darkly staining cells and large, pale staining cells which are usually laterally located in the nucleus. Like NMM, NML is better developed in lizards with more complex papillae basilares. Nucleus laminaris may be represented by a few fusiform cells in the ventral portion of the NML region.
Horizontal cell axons and axon terminals in goldfish retina
Authors: Stell William K. 
Published: January 2005

AbstractRetinas of ordinary and black moor varieties of goldfish (Carassius auratus) were prepared by the Golgi method, mounted flat or sectioned vertically, and studied in the light microscope. Three types of horizontal cells whose dendrites contact only cones, and one type whose dendrites contact only rods, were observed. The cone horizontal cells (Cajal's “external horizontal cells”) all have slender axons which descend gradually to the inner nuclear layer and terminate there in long, fusiform expansions (Cajal's “internal horizontal cells”). The thin and thick portions of the axons, as well as the perikarya of the horizontal cells, bear small numbers of straight, horizontally‐directed, knobby filamentous appendages which may be sites of synaptic contact. The cone horizontal cell axons in goldfish, unlike those in higher vertebrates, do not terminate in contact with synaptic endings of photoreceptor cells, but in proximity to cells and processes deep in the inner nuclear layer. Axons have not yet been demonstrated on rod horizontal cells in goldfish.
Scanning and transmission electron microscope studies of interkinetic nuclear migration in the cerebral vesicles of the rat
Authors: Seymour R. M. , Berry M. 
Published: January 2005

AbstractA scanning electron microscope (SEM) was used to examine the morphology and surface texture of neuroepithelial cells during interkinetic nuclear migration in the cerebral visicles of the rat at 12, 13 and 14 days of gestation. Serial sections of embryonic material of the same age were also prepared for the transmission electron microscope (TEM). Particular attention was paid to the SEM and TEM appearance of mitotic neuroepithelial cells which occur exclusively along the ventrivcular border of the neural epithelium. Three distinctly‐shaped classes of mitotic cells were recognised in sacnning micrographs. (1) Pyriform cell. This type of mitotic cells was characterised by the presence of very long, fin procsses rediating from the tip and shoulders of a short external (basal) process. These fine processes were temed “intramitoticfilopodia” Microvilli were found on the surface of most pyriform cells. (2) Conical cells. Thee lacked an external process but there were large numbers of intramototic filopodia at the basal pole of the cell body, and the perkikaryal surface was rich in microvilli. (3)Globular cells. It was possible to subdivide this class of cell into large and small types. An external process and microvilli were absent in globuar cells of both sizes, but usually a few short intramitotic filopodia were absent in globlar cells of both sizes, but usually a few short intramitotic filopodia were present at the bnasal pole. The perikaryal surfced of the globular population were reised in coarse liums and bubble‐like protrusions.By pooling TEM and SEM information we were able to deduce that pyriform cells probably possess a prphase or prometaphase chromosome morphology, While conical cells exhibit a chromosome morphologyu somewhere between prometphase and early anaphase. Lrge globular mitotic cells were found to be between metaphase and late anaphase and small glbular cells were indentified as early telophase cells.On the basis of these findings we have proposed that as a bipolar neuroepithelial cell rounds up for motosis it passes first through a pyriform state during which the external process is retracted or broken down, and then through a conical stage when the cell consolidates its position on the verntricular surface. Finally, the cell enters a large gobular stage before dividing into two small filopodia play in this procss of rounding up.
The development of synapses in the visual system of the cat
Authors: Cragg B. G. 
Published: January 2005

AbstractSynapses have been counted by electron microscopy and neurones by light microscopy through the depth of the visual cortex in a series of cats from 37 days gestation to adulthood. A few definite synapses are present as early as three weeks before birth, but there is then a latent period of four weeks before synapses increase rapidly in number 8–37 days after birth. The synapses occur just above and just below the cell plate at first, but in the adult cat they become evenly distributed in the depth of the cortex. The gradual separation of neurones by neuropil during development precedes a parallel increase in the density of synapses by about one week. The average number of synapses associated with one neurone rises to a peak of about 13,000 at seven weeks after birth. The densities of synapses and of neurones subsequently fall to slightly lower values in adult cats as the glial cells continue to develop.The timing of synaptic development in the visual cortex has been compared quantitatively with that in the L. G. N. and qualitatively with synaptogenesis in the retina. Synapses develop in the L. G. N. and cortex in a parallel fashion, and the L. G. N. precedes the cortex by a short interval of about two days. In the cell plate of the retina a few receptor synapses are present nine days before birth. Inner plexiform synapses are also present at this time, but ribbon‐containing synapses do not appear until birth. Very few receptors possess outer segments with discs at birth, but five days later disc‐bearing outer segments have developed.Thus synaptic development starts before afferent impulses can enter the visual system, but the main increase in synapses in the L. G. N. and cortex takes place four weeks after the start of synapse formation while the visual system is being used.
Quantitative relationships between nerve and satellite cells in spinal ganglia: An electron microscopical study. II. Reptiles
Authors: Pannese Ennio , Ventura Raoul , Bianchi Rossella 
Published: January 2005

AbstractIn the spinal ganglia of two species of reptiles (gecko and lizard) the volume of the perikaryal satellite cell sheath was found directly proportional both to the volume and surface area of the related neuronal body. This result agrees with that obtained in a previous research on two species of mammals (cat and rabbit). A quantitative balance between neuronal bodies and their associated glial tissue therefore exists also in the spinal ganglia of zoological species phylogenetically quite distant from mammals.The quantitative relationship between glial and nerve tissue was found to be lower in the gecko and lizard than in the cat and rabbit. This difference could have a phylogenetic significance, and/or it could be explained by the lower metabolic rate in the nervous system of the poikilotherms in respect to mammals.
Human brain in tissue culture. II. Studies of long‐term cultures
Authors: Wroblewska Zofia , Devlin Mary , Gilden Donald H. , Santoli Daniela , Friedman Harvey , Koprowski Hilary 
Published: January 2005

AbstractThis paper describes the techniques used to maintain and reconstitute from storage adult human brain cells in culture. Growth characteristics, cell morphology, lifespan, and karyotypic analysis of cell lines derived from patients with multiple sclerosis (MS), non‐MS neurologic diseases, and normal brains are compared.
Human brain in tissue culture. IV. Morphological characteristics
Authors: Rorke Lucy Balian , Gilden Donald H. , Wroblewska Zofia , Santoli Daniela 
Published: January 2005

AbstractThe morphology of cells from normal and diseased brains and PML‐SV40 transformed brain cells grown on glass cover slips in culture is described. Seven types of cells are identifiable, four of which are probably of mesenchymal origin whereas the remaining three are neuroglial. A classification on the basis of the morphologic features is presented.
Axonal numbers and sizes in the connectives and peripheral nerves of the leech
Authors: Wilkinson Joyce M. , Coggeshall Richard E. 
Published: January 2005

AbstractThe present study is an electron microscopic analysis of the numbers and sizes of axons in the connectives and nerves of the medicianal leech. In either the right or left connectives for ganglis 14–18, there are approximately 2860 (± 294 S.D) axons. Ninety‐seven percent of these axons are less than one micron in diameter. The median connective, Faivre's nerve, contains 97 (± 3 S.D.) axons, and 94% of these fibers are smaller than one micron. In the peripheral nerve roots for ganglia 14–18, there are approximately 2351 (± 311 S.D.) axons. Ninety‐eight percent of the axons in the nerves are less than one micron in diameter. Thus, there are approximately 20,000 axons associated with each of the segmental ganglia 14–18 in the leech, and the vast majority of these fibers are less than one micron in diameter.
The projection of the retina upon the optic tectum of the pigeon
Authors: Hunt S. P. , Webster K. E. 
Published: January 2005

AbstractThe projection of the retina onto the optic tectum of the pigeon has been investigated using silver impregnation methods for degenerating axons and terminals, autoradiographic tracing, and the Golgi methods. Degenerating optic afferents distribute to sublaminae a–d and f of the stratum griseum et fibrosum superficiale over the whole tectum, but two major fields are observed. One occupies the caudal and ventral tectum (in which region laminar cytoarchitecture is marked), and the other rostral and dorsal tectum (where demarcation of cell laminae is relatively poor). Degeneration in the latter field is coarse and clearly distributes in a distinctly laminated fashion within the stratum griseum et fibrosum superficiale. In contrast, degeneration in the caudo‐ventral region is fine, and laminated distribution less clear. The evolution of the degeneration pattern over survival periods from 3 to 56 days suggests that these laminar distributions reflect the existence of several different types of optic terminal ramification present in all parts of the tectum. A selective laminar distribution of such optic afferent types correlates well with our own and other Golgi studies. The results of the autoradiography experiments are broadly compatible with these findings.
Radiation‐induced interference with postnatal hippocampal cytogenesis in rats and its long‐term effects on the acquisition of neurons and glia
Authors: Bayer Shirley A. , Altman Joseph 
Published: January 2005

AbstractThe long term consequences of graduated interference with the acquisition of hippocampal neurons and glia during early infancy were examined with quantitative histology and 3H‐thymidine autoradiography. The head region containing the hippocampus was irradiated from day two on with either two (2X), four (4X), six (6X) or eight (8X) doses of 150–200r X‐rays. The animals were killed at 30, 60, 90 and 120 days of age.The morphology of the hippocampus was normal in all irradiated groups with the characteristic interlocking folds of the pyramidal and granular layers. While the number of pyramidal cells of Ammon's horn was unaffected, the number of granule cells of the dentate gyrus was progressively and permanently reduced from control levels by the different dosage schedules (2X, 59% reduction; 4X, 77%; 6X, 83%; 8X, 84%). Incidental observations in control animals indicated a 20% increase in granule cells between 30 and 120 days of age in agreement with earlier observations of granule cell labelling after 3H‐thymidine injections in adult rats.The time of origin of the approximately 15–16% of the granule cells surviving irradiation in the 8X group was determined by injecting either pregnant females (gestation days 19–20) or pups (days 0 and 1) with two successive doses of 3H‐thymidine; the animals were irradiated from day two on with eight X‐ray doses. The granule cells surviving in the postnatally injected group were all unlabelled and comparable in number to the unlabelled cells in control animals that were given five successive postnatal injections of 3H‐thymidine. This established that the radioresistant complement of granule cells is formed prenatally. In the prenatally injected group, over half the surviving cells were labelled; it was assumed that those not labelled were formed before gestation day 19.In contrast to the permanent reduction in the number of granule cells, there was some reestablishment of the number of cells in the dentate molecular layer and the Ammonic stratum oriens; in the fimbria, recovery in cell number was complete by 60 days. In a supplementary autoradiographic experiment, cell proliferation in the granular layer and in the fimbria was determined at 60 days of age after a single postnatal injection of 3H‐thymidine on either day 15 or day 20 in the control, 2X, 4X and 6X groups. The number of labelled cells in the irradiated groups was always well below control levels in the granular layer, but it was either above or at the same level as controls in the fimbria. Tentative interpretations were offered for the differential long‐term effects of variable X‐ray schedules on the neuronal and glial populations of the hippocampus.
A quantitative analysis of the cat retinal ganglion cell topography
Authors: Hughes A. 
Published: January 2005

AbstractA retinal ganglion cell distribution map has been prepared for the cresyl violet stained cat retina. It differs from previously published maps in revealing the visual streak to be more substantial and in showing a higher peak density of 9–10,000 ganglion cells/mm2 at the presumed visual pole. The map was used to obtain a minimum estimate of the retinal ganglion cell population as 217,000 cells, more than double the total previously reported. The problem of classifying the cells of the ganglion cell layer is discussed in detail and examples of criterion cells illustrated. The paper also includes an account of retinal mensuration (dimensions, area, etc.) and a discussion of the visual streak orientation.
Retinogeniculate projections in albino and ocularly hypopigmented rats
Authors: Creel Donnell , Giolli Roland A. 
Published: January 2005

AbstractThe retinogeniculate fiber projections were studied by degeneration methods in several strains of rats with pigmentation in their eyes and pelts ranging from the intensely pigmented self phenotype to the albino. The ipsilateral retinogeniculate input in the self, Irish, and hooded rats, and rats with “bicolor fundus” is located medially within the dorsal lateral geniculate nucleus (LGd) and is seen as a single lamina of moderately dense degeneration. The contralateral retinogeniculate input in these ocularly pigmented rats is a dense network of degeneration covering all of the LGd except for the region receiving the ipsilateral input which is an area of sparse degeneration forming a “pocket.” There is a general paucity of ipsilateral fibers in albino rats. The ipsilateral projections in albino, light‐eyed cream‐pelted rats, and the rats with heterochromia irides is seen as several fragmented laminae. The contralateral input to the LGd is evenly distributed, is dense throughout and lacks any discernible “pocket” of sparse degeneration. Only the presence of melanin pigment of optic cup origin appears to correlate positively with the development of normal retinogeniculate projections. Variability was found between animals regardless of the degree of pigmentation shown by the animal. There would appear to be enough genetic modifying factors inducing variation of these fiber projections that the appearance of a particular pattern of input to the LGd should be considered as having only a statistical probability of occurrence.