bluuebunny/crossref_metadata_2025_split huggingface dataset:
The interstitial cell and its place in the concept of the autonomic ground plexus
Authors: Rogers Donald C. , Burnstock Geoffrey 
Published: January 2005

Abstract1. The autonomic interstitial cells have been studied in the toad small and large intestine and guinea‐pig taenia coli by means of both the light and electron microscopes. The guinea‐pig superior cervical ganglion has also been examined.2. Apart from muscle cells, neurons and Schwann cells, at least one other cell type has been observed. These cells have been designated connective tissue cells on the basis of their gross form, fine structure and relation to other cells. In many respects they resemble fibroblasts and macrophages.3. These cells are in close relation to nerve fiber bundles and smooth muscle cells. They often form a complete sheath around bundles of axons and Schwann cells. Many of the processes of the connective tissue cells lie in grooves on the surface of the muscle cells; the distance between apposing cell membranes is about 200 Ä.4. The processes of the connective tissue cells often interdigitate with each other in a most complex manner, the opposing cell membranes being about 200 Ä apart. Such a close relationship would appear with the light microscope to be a fusion forming a syncytium.5. Observation with the light microscope on the terminal ramifications of the autonomic nervous system where small bundles of fine axons are enclosed by connective tissue cells could give rise to the impression that they contained “neurofibrils.”6. It is suggested that the term autonomic interstitial cell covers a number of cell types which have been confused. The cells designated connective tissue cells along with Schwann cells have between them the characteristics of the autonomic interstitial cells as described by previous workers. Cajal's original description of sympathetic interstitial cells was actually a description of connective tissue cells.
Autoradiographic and histological studies of postnatal neurogenesis. I. A longitudinal investigation of the kinetics, migration and transformation of cells incoorporating tritiated thymidine in neonate rats, with special reference to postnatal neurogenesis in some brain regions
Authors: Altman Joseph , Das Gopal D. 
Published: January 2005

AbstractNeonate rats were injected systemically with thymidine‐H3 and killed after different periods of survival. Cell proliferation, migration and transformation in the brain were studied autoradiographically. It was established that cells multiplying in the ependymal and subependymal walls of the olfactory ventricle migrate outward into the olfactory bulb, where they become differentiated into granule cells. These postnatally formed granule cells contribute to the formation of the granular and several other layers of the olfactory bulb. Cells multiplying at a high rate in the wall of the lateral ventricle migrate to the hippocampus and contribute to the formation of the granule cells in the granular layer of the dentate gyrus. Cells multiplying at a high rate in the external and internal granular layers of the cerebellum become differentiated into granule cells, and, to a lesser extent, other types of nerve cells of the cerebellar cortex. Evidence was also obtained of the postnatal origin of many of the granule cells of the cochlear nucleus. Postnatal neurogenesis is restricted to these short‐axoned granule cells or microneurons; the long‐axoned nerve cells or macroneurons of the brain are formed prenatally.
Nervous system of the snail Helix aspersa. I. Structure and histochemistry of ganglionic sheath and neuroglia
Authors: Fernandez Juan 
Published: January 2005

AbstractThe ganglionic sheath is structured upon a complex fibrocellular framework. A tridimentional network of anastomosed connective tissue lamellae constitutes the extracellular space. In the deep ganglionic region these lamellae display alkaline phosphatase activity. Sheath cells appear embedded in network fenestrae. The most peculiar of these are the superficial voluminous globular cells. Its cytoplasm appears built of a lipoprotein network containing glycogen and “lipofuscin pigments.” These two latter substances appear to undergo seasonal changes. The gland cells seem to be unicellular endocrine glands, containing many droplets giving positive reaction for carbohydrates, lipids and proteins. Muscle cells are placed throughout the sheath. The cytoplasm gives an intense reaction for proteins but does riot exhibit myofibrilles. These cells could play an important role in ganglonic movements and in addition could modify the amplitude of the extracellular sheath space. Pigment cells, containing melanin granules, are distributed among the other sheath cells. Cellular groups of the sheath show many large spheroidal mitochondria and sudanophilic droplets. These cells could be involved in the synthesis of some unknown substance or/and in metabolic transport across the sheath. Glial cells are located under the sheath and surrounding the entire neuronal surface. The cytoplasm appears connected with alkaline phosphatase and with an acidic substance. The histochemical and topographical characteristics of these cells point to their role in metabolic transportation, mechanical support and nervous homeostasis.
Increases in cortical depth and glia numbers in rats subjected to enriched environment
Authors: Diamond Marian C. , Law Fay , Rhodes Helen , Lindner Bernice , Rosenzweig Mark R. , Krech David , Bennett Edward L. 
Published: January 2005

AbstractWe have previously reported anatomical and chemical changes in the cerebral cortex of rats living in an enriched, stimulating environment. The present study includes additional histological measures such as more extensive depth measures, differential cell counts, and cell size measurements.Celloidin‐embedded, thionin‐stained sections of the visual cortex from environmentally enriched rats and their impoverished littermates were measured. Two methods for calculating cortical depths were used: one, with an ocular micrometer taking eight measures lateral to the elevation in the corpus callosum on each hemisphere; two, on enlarged photographs taking 51 measurements 2 mm apart on each hemisphere. With the ocular micrometer method the cortical depth of the enriched brains was 6.4% greater than the depth of the impoverished cortex. On the enlarged photographs the more medial depths in the enriched rats showed greater increases than the lateral depths.Overlapping photomicrographs were made of a medial cortical area 1.00 mm by 0.75 mm on each transverse section and were combined into one composite picture for each animal. Differential cell counts from the composite pictures were determined independently by two technicians. Results indicate a 14% (p<0.01) increase in glia among the enriched rats. No significant differences between enriched and impoverished groups were found in the perikarya and nuclear circumferences as measured with a planimeter from camera lucida drawings.
Cortical projections to brain stem and spinal cord in the goat by way of the pyramidal tract and the bundle of Bagley
Authors: Haartsen Adrianus Bartholomeus , Verhaart Willem Jozef Cornelis 
Published: January 2005

AbstractIn this paper the cortical fibers in the brain stem of the goat are studied. The preparations were stained according to the method of Nauta‐Gygax. It was proved that the fibers descend both through the pyramidal tract and Bagley's corticotegmental tract. The latter terminates in the ipsilateral trigmidal spinal tract nucleus and the lateral part of the reticular formation of the medulla, but pyramidal fibers do not terminate in the first nucleus. At the transition of the medulla and the cord three pyramidal tracts, all consisting of both direct and crossed cortical fibers enter the cord, whereas in all probability the fibers of Bagley's tract do not reach the cord. A ventral intercommissural tract carries the majority of the fibers, it reaches the seventh cervical segment. A small lateral tract in the lateral funiculus and a dorsal in the dorsal funiculus reach the third and the second cervical segments. The site of origin of Bagley's tract appeared to be identical to that of the medullary pyramid.
The development of hippocampal and dorsolateral pallial regions of the cerebral hemisphere in fetal rabbits. III. Twenty‐nine millimeter stage, marginal lamina
Authors: Stensaas L. J. 
Published: January 2005

AbstractThe structure of the cerebral hemisphere of 29 mm rabbit embryos was stuided with aniline and Golgi stains. Particular attention was devoted to the structure of the marginal lamina. In aniline stained sections it is a light, relatively acellular layer at the surface of the embryonic cerebral hemisphere and corresponds to layer I, the molecular layer, of the adult cerebral cortex. Even in early embryonic stages the marginal lamina consists mainly of terminal remifications of pyramidal cell apical dendrites and ascending axons. This layer of neuropile is of particular interest since it greatly precedes the development of other cortical zones rich in axons and dendrites. The reasons for the precocious development of dendritic branches at this level are unknown but may be related to the presence of ascending axons of nerve cells in the cortical plate or to horizontal cells.Large and small horizontal neurons are the only intrinsic cells at this level. Axons are present on the small elements, but were seen only infrequently on large cells. Some of the latter are similar to Cajal‐Retzius cells of perinatal stages, but have relatively few ascending branches.
Differential projections of habenular nuclei
Authors: Akagi Katsuhito , Powell Ervin W. 
Published: January 2005

AbstractLesions were made in the lateral and medial habenular nuclei of the cat. Subsequent degeneration of nerve fibers and terminalis was studied using Nauta‐Gygax silver technique. The medial and lateral habenular nuclei project differentially to the septum, olfactory, tubercle, thalamus, midbrain tegmentum and tectum. The diffuse part of the habenulopeduncular tract rises from the lateral habenular nucleus and the compact part rises from both nuclei. Degenerating terminals were seen caudally in the following nuclei: interpeduncular, central superior, dorsal raphae, ventral tegmental (from the medial habenular nucleus), dosral tegmental (from the lateral habenular nucleus), pretectal area, superior colliculus and inferior colliculus (from the lateral habenular nucleus). Rostral projections course in the medial part of the stria medullaris from the medial habenular nucleus and in the lateral part of the stria medullaris from the lateral habenular nucleus: Degenerating terminals were seen rostrally in the following nuclei: dorsomedial, anteroventral, anterodorsal, paraventricular, posterior medial septal (from the medial habenular nucleus) and preoptic area (from the lateral habenular nucleus). Projections occur from the medial habenular nucleus to the amygdala via the stria terminalis.The habenular nuclei are considered to be structures of the limbic system which are differentially related to midbrain, thalamic, amygdaloid, septal and preoptic structures via feedback circuits.
Neuronal organization in long term cultures of the spinal cord of the fetal mouse
Authors: Sobkowicz Hanna M. , Guillery R. W. , Bornstein Murray B. 
Published: January 2005

AbstractExplants of spinal cord from 14–16 day old fetal mice were cultured for 18–54 days in vitro. They were fixed and stained with cresyl violet or the Holmes method. In most explants a basic pattern of cell and fiber architectonics was recognizable. In many aspects the pattern seen in the explants resembles the structure of the spinal cord at the time of explantation, and some of the same cell groups are present in both. Most explants resmble a transverse section of spinal cord. A ventral commissure and dorsal and ventral roots are readily identified. In addition, two characteristic circular bands of fibers form around the periphery of the explants.Many axons in the ventral roots arise from large ventral horn cells and form terminal arborizations at some distance from the explants. These axons are comparable to in vivo ventral root fibers. The fibers in the dorsal roots, however, are generally fibers that deviate from the circular bands and return again, thus forming extensive loops. The circular bands may represent regenerated axons of long association pathways.The structure of these explants demonstrates that pieces of nervous tissue grown in complete isolation can maintain much of their internal organization. Their axons appear to follow relatively constant growth patterns which are characteristic for particular cell types and, to a certain extent, appropriate to the pattern that would be formed in vivo.
Microanatomy of crayfish thoracic cord and roots
Authors: Sutherland Rodrigue M. , Nunnemacher Rudolph F. 
Published: January 2005

AbstractFor a thorough understanding of the functions of the crustacean nervous system a knowledge of all its components is necessary. The use of the electron microscope provides accurate data of the number, size, and distribution of fibers in nerve tissue. Nerve fiber counts determined by electron microscope mapping show increases of 20 to 60% in the number of fibers over those determined by light optics. In Orconectes, the number of fibers reach close to 9,500 in the thoracic cord, 20,000 in the main walking leg roots, and 83,000 in the main claw leg roots. Fiber size distributions indicate general motor and sensory patterns of function in the thorax. High percentages (97–99) of fine and small fibers in the roots to the legs suggest the presence of multitudinous sensory‐associated organelles.
A quantitative electron microscopic study of myelination in the pyramidal tract of rat
Authors: Samorajski T. , Friede R. L. 
Published: January 2005

AbstractThe ultrastructure of fibers during myelin formation in the pyramidal tract of rats is described. The distribution of fiber classes based on counts of myelin lamellae was determined for newborn, young and mature rats. In newborn rats (2–12 days), growth of the axon was extremely rapid in fibers undergoing early myelination, resulting in greater variation in the relation between axon circumference and sheath thickness and, also, in the presence of myelin sheaths that were unusually thin in relation to the size of the axons. In young rats (12 days to 8 weeks), the numbers of myelin lamellae present in the sheaths increased in proportion to the increase in axon circumference. In adult rats, the numbers of myelin lamellae present in the sheaths was in linear relation to axon circumference for all sizes of myelinated fibers. Approximately 20% of the fibers were nonmyelinated. The number of glia cells per axon at the onset of myelination was approximately 20% of the adult ratio. During growth, myelination gliosis resulted in a steady increase in the number of glia cells per axon until adult levels were ultimately achieved. Our observations suggest that formation of myelin lamellae by oligodendroglia cells may be controlled by the caliber of the axon.
Discontinuities in the dorsal lateral geniculate nucleus corresponding to the optic disc: A comparative study
Authors: Kaas J. H. , Guillery R. W. , Allman J. M. 
Published: January 2005

AbstractA cylindrical cellular discontinuity commonly occurs in lateral geniculate layers that are innervated by the contralateral eye. Such a discontinuity has been found in a variety of mammalian species, including carnivores, primates, a rodent and a marsupial. Electrophysiological evidence obtained from some of these species shows that the discontinuity corresponds to the blind spot. It is concluded that the representation of the retina within the lateral geniculate nucleus is extremely accurate, since the retinal receptor layer and the geniculate layers have corresponding holes.Two possible mechanisms that would demand such a discontinuity are considered. One is an intralaminar mechanism in which the cells in each lamina accurately reflect the distribution of retinal receptors; the other is an interlaminar mechanism in which the representations of the homonymous hemiretinae are so accurately aligned that the optic disc must be represented by a cellular discontinuity.
Proliferation in the neural tube of the splotch (Sp) mutant mouse
Authors: Wilson Doris Burda 
Published: January 2005

AbstractThe length of each period in the cell cycle was determined radioautographically for mesencephilic ventricular cells in splotch normal (Sp/+;+/+) and abnormal (Sp/Sp) mouse embryos. At ten and 11 days' gestation, the length of the generation time in the abnormal brain was approximately 3.5 hours longer than that in the normal littermates. This overall prolongation was the result of an increase in the DNA‐synthetic (S), mitotic (M), and postmitotic (G1) periods. The increase in the length of mitotis appeared to be responsible for the increased numbers of mitotic figures which characterize this condition. The abnormal brains, however, showed a typical chronological lengthening of the cell cycle of approximately the same magnitude as is the case during normal development of the neural tube.
Evidence of a pallidohabenular pathway in the cat
Authors: Nauta Haring J. W. 
Published: January 2005

AbstractThe efferent projections of the entopeduncular nucleus (internal segment of the globus pallidus) in the cat have been studied by the autoradiographic tracing method. The findings reported in this article strongly suggest the existence of a substantial pathway originating in the internal segment of the globus pallidus and terminating in a large, circumscript region of the lateral habenular nucleus. Axons of this pathway follow a wide variety of routes to reach the lateral habenular nucleus. The implications of these findings are discussed in relation to the problem of connections between the limbic system and the corpus striatum.
Fibers in the ventral spinal nerves of the frog
Authors: Sutherland Rodrigue M. , Nunnemacher Rudolph F. 
Published: January 2005

AbstractThe use of the electron microscope provides accurate data of the number, size, and distribution of fibers in nerve tissue. Nerve fiber counts determined by electron microscope mapping show increases of two to seven times in the number of fibers over those determined by light optics. The combined counts of fibers, on one side in Rana pipiens, from the ventral spinal nerves (1, 2, and 3) supply the forelimb with 14,000 fibers; from spinal nerves (4, 5, and 6) to the trunk, 4,050 fibers; and over 20,000 fibers from the ventral spinal nerves (7, 8, 9, and 10) pass into the sciatic and crural nerves which innervate the hind limb. The greatest total number of fibers, and especially of small and fine fibes, are in the second and ninth spinal nerves. Of all the nerves studied, the sciatic contains the greatest number of fibers (16,500). The high numbers and percentages of fine and small fibers in the spinal, sciatic, and crural nerves emphasize the importance of determining the function of these fibers.
Patterning in synaptic knobs which connect with Mauthner's cell (Ambystoma mexicanum)
Authors: Kimmel Charles B. , Schabtach Eric 
Published: January 2005

AbstractThe Mauthner's cells (M‐cells) of the young axolotl larva receive a rich afferent supply of synaptic knobs (club and bulb synapses). The knobs may be classified into at least five types according to their ultrastructure after direct fixation in OsO4. The different types are non‐randomly arranged on the M‐cell surface such that groups of knobs of the same type are frequently observed to form a cluster or patch. The M‐cell surface pattern is thus a mosaic of such clusters. Different types of knobs may be restricted to different locations on the M‐cell; one type is found almost exclusively with the M‐cell lateral dendrites, and another two types with the axon hillock and axonal initial segment. The dorsal perikaryon is nearly devoid of knobs. This pattern is at least in part related to the pattern of fasciculation in the adjacent neural tissue, and it is likely that all or some of the distinctive types of knobs originate from different kinds of neurons.The pattern of distribution of the synaptic knobs appears to increase in complexity during development, and this can be related to the asymmetrical growth of the M‐cell during its maturation. These observations are discussed with reference to theories of neuronal specificity.
Olfactory bulb projections in the bichir, Polypterus
Authors: Braford Mark R. , Northcutt R. Glenn 
Published: January 2005

AbstractThe central projections of the olfactory bulb were studied in Polypterus using the Nauta and Fink‐Heimer techniques. Two major target areas were identified in the subpallium: the lateral subpallial nucleus and the dorsal and ventral entopeduncular nuclei. The connections are predominantly, if not exclusively, ipsilateral. In the pallium a massive ipsilateral projection to the superficial third of the medial pallium was demonstrated while the remainder of the pallium was found to be free of degeneration. Thus it appears that the pallium of Polypterus is not uniform throughout, as has been suggested in the literature. This contention is also supported by an analysis of the pallial cytoarchitecture. Because the pallium of Polypterus is everted, rather than inverted and evaginated, the topographically medial pallium is in topological correspondence with the lateral pallium of tetrapods. On the basis of this topological correspondence and the similarity of afference from the olfactory bulb, it is argued that the “medial” pallium of Polypterus is homologous to the pyriform pallium of tetrapods. The findings of this study are compared to those of similar studies in teleosts, which also have an everted pallium. An apparent conflict appears and suggestions for resolving it are offered.