bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies of the spinal cord of Galago senegalensis, Compared to that in man
Authors: Bossy J. G. , Ferratier R. 
Published: January 2005

AbstractThe material for this study of the spinal cord of Galago consisted of five specimens, and, for comparison, all the segments of a human spinal cord.The spinal cord of Galago is very similar to that of the human fetus, which is not as well defined as in the adult. The lumbar enlargement is as great as the cervical one. The examination of cross‐sections reveals a significant reduction in the area of the funiculus posterior, which places this animal between rabbit and bear in this regard. However, its relative percentage graphs are very close to those of the rhesus monkey.A cytoarchitectonic study of Galago shows that its neurons are relatively larger than those in man. Topographic cell distribution in this species is very similar to that of man. The areas of the limbs seem to have no correspondence to other regions of the spinal cord.On the whole, in spite of the specialization of movements of the head and hindquarters, the spinal cord of Galago shows a lesser degree of differentiation.
Afferent connections of the facial nerve
Authors: Rhoton Albert L. 
Published: January 2005

AbstractThe central connections of the afferents of the facial nerve have been studied by the Nauta‐Gygax and Fink‐Heimer techniques in the rat, cat, and the rhesus, cynomolgus, and squirrel monkeys.Descending components that entered the spinal V and solitary tract were found in all species studied. The spinal V fibers terminated in the upper cervical dorsal horn, making a minor contribution to the various subdivisions of the spinal V nucleus, and are probably concerned with pain; the solitary fibers terminated in the solitary nucleus, predominantly at levels rostral to the obex. A few degeneration fibers were seen in reticular formation medial to the spinal V tract in all species.An ascending component was found in both the cat and monkey. The identification of some fibers from cranial VII, which ascend and terminate on a prefacial, probably gustatory, portion of the solitary nucleus provides the first confirmation in nerve degeneration studies of Nageotte's results in man. Some ascending fibers also terminated on the most medial cells of the main trigeminal sensory nucleus, a connection not previously described, that probably mediates touch from the auricular region. Another previously unreported connection found only in the monkey was that of some fibers which terminated on a nucleus (paratrigeminal nucleus), dorsolateral to the spinal V tract; this nucleus may represent an oral extension of the lateral cuneate nucleus, and if this is so, the axons terminating in it would be a part of the afferent cerebellar system.
Nuclear configuration of the diencephalon in some lorisoids
Authors: Kanagasuntheram R. , Wong W. C. , Krishnamurti A. 
Published: January 2005

AbstractThe nuclear configuration of the diencephalon of Galago and slow loris is described and a comparison is made with that of other prosimian primates. The nuclear organization in both Galago and slow loris is generally similar to that described for other mammalian forms. However, the thalamus of slow loris shows certain progressive features over that of Galago (a) in the absence of a parvocellular portion for the nucleus ventralis anterior, (b) in the predominance of the parvocellular portion for the nucleus medialis dorsalis and (c) in the size and pattern of lamination of the lateral geniculate body. Moreover, it is remarkable that the lateral geniculate body of Galago has only five layers while the six layered pattern is seen in slow loris.In the preoptic and the hypothalamic regions the nucleus hypothalamicus dorsomedialis and nucleus supraopticus are unusually well developed in slow loris while the other hypothalamic and preoptic nuclei are better defined in the brain of Galago. Nevertheless, differences in the external morphology of the brain along with the greater differentiation of the thalamic nuclei in slow loris make it possible to conclude that the brain of this animal is more advanced than that of Galago.
Some findings concerning the relationship between ontogenesis and cytoarchitecture of the primate brain
Authors: Schneider Hans‐Rudolf 
Published: January 2005

AbstractThe scattering of different primate sub‐ and hypothalamic cells as some sort of individual variability and its probable connection with ontogenesis (especially with the spread of fiber systems and blood vessels) are shown to have certain consequences for cytoarchitecture, stereotaxic work and the problem of the neurons' form‐function relationship.
Efferent fiber connections of the marmoset (Oedipomidas oedipus) trigeminal nucleus caudalis
Authors: Dunn Jon D. , Matzke Howard A. 
Published: January 2005

AbstractA study was made of the efferent fiber connections of the trigeminal nucleus caudalis in the marmoset monkey (Oedipomidas oedipus). Degeneration resulting from nucleus caudalis lesions in twelve animals was studied by the Nauta technique. Following lesions of the trigeminal nucleus caudalis, degeneration was present bilaterally in the medial reticular formation, medial and spinal lemnisci, ventral horn and nucleus cuneatus. Ipsilateral preterminal degeneration was observed in the intermediate, hypoglossal, supraspinal and retroambigualis nuclei, the trigeminal interpolaris, oralis and main sensory nuclei, and motor nuclei of V and VII cranial nerves. An ipsilateral intranuclear trigeminal path is described. Nucleus caudalis efferent connections with the thalamus are discussed.
The basilar pontine gray of the opossum (Didelphis virginiana). I. Morphology
Authors: King James S. , Martin George F. , Biggert Thomas P. 
Published: January 2005

AbstractThe basilar pontine nuclei were described for the opossum in Nissl stained, serial, transverse sections, and named (dorsal, ventral, medial, and lateral) with reference to the pontine pyramidal bundle. The details of neuron morphology were determined by employing Nissl stains and the Golgi technique. The neuron cell bodies of the basilar pontine gray were round, oval or spindle in shape and displayed little angularity. Measurements of neuronal perikaryia indicated a size range of from 8 to 20 μ. The Nissl substance appeared finely granular with some cells displaying large discrete granules. Dendrites observed in Golgi preparations either extended some distance from the perikaryon or ended adjacent to the cell body in terminal arborizations. The phylogenetic significance of the nucleur groups and the primitive condition of a limited pre‐trigeminal basilar pons is discussed.
Central auditory system of the kangaroo rat, Dipodomys merriami
Authors: Webster Douglas B. , Ackermann Robert F. , Longa Giampaolo C. 
Published: January 2005

AbstractKangaroo rat brains were studied grossly and microscopically and with several types of histological preparations to describe for the first time this animal's central auditory system and to determine whether previously described peripheral modifications are correlated with central modifications.With but one exception each nucleus of the central auditory system of the kangaroo rat is prominent and easily distinguished. The medial superior olivary nucleus and the dorsal nucleus of the lateral lemniscus are especially hypertrophied. The dorsal cochlear nucleus, composing most of the large area acoustica, is organized into three cell‐type layers. The ventral cochlear nucleus is morphologically divided into six regions, corresponding to the scheme of Harrison and Irving for the albino rat but with serveral important differences.The spindle‐shaped cells of the lateral and medial superior olivary nuclei are of two types: one in narrow (8 μ) and stains deeply in Nissl stains; the other is broader (15 μ) and stains lightly in Nissl stains.A group of large multipolar cells lying between the dorsal nucleus of the lateral lemniscus and the base of the inferior colliculus is described for the first time; their connections are undetermined.The possible significance of the prominent central auditory system is descussed briefly and related to the proposals of other workers for animals previously described.
Cellular and chemical changes during myelination: Histologic, autoradiographic, histochemical and biochemical data on myelination in the pyramidal tract and corpus callosum of rat
Authors: Schonbach J. , Hu K. H. , Friede R. L. 
Published: January 2005

AbstractA quantitative study of myelination in the pyramidal tract and in the corpus callosum of rat was undertaken to establish the order and the possible correlation of various cellular and chemical changes in the tissue.Myelination was initiated by a period of thymidine‐H3 labeling of nuclei and g±al proliferation, resulting in a rapid increase in the cell density or “myelination gliosis.” Slightly later, there was an increase in NAD‐diaphorase activity and in leucine‐H3 uptake in both the glia cells and throughout the tissue. The formation of myelin sheaths began when myelination gliosis was established; it overlapped the periods of high enzyme activity and high leucine‐H3 uptake. Cell proliferation continued during myelin formation after the onset of myelination gliosis; the cell density in the pyramidal tract decreased during this period, probably because the spacing of the cells increased due to the growth of the myelin sheaths. Staining of myelin sheaths was estimated with a semi‐quantitative method and paralleled an increase in biochemical assays of total cholestrol. The significance and possible interrelations between the morphological and chemical changes during myelination are discussed.
Distribution of dorsal root fibers in the medulla oblongata of the cat
Authors: Rustioni A. , Macchi G. 
Published: January 2005

AbstractAfferent fibers to the medulla oblongata of the cat were studied in 25 animals following section of one or more dorsal roots.Using the Nauta‐Laidlaw stain a map was constructed of the distribution of the fibers to the dorsal column nuclei and a survey made of the afferents to other bulbar nuclei: nucleus cuneatus lateralis, lateral reticular nucleus, descending root of the fifth cranial nerve and the nucleus tractus solitarii.In the intermediate segment of the nucleus gracilis and the caudal two thirds of the nucleus cuneatus, there is a somatotopical arrangement with a dorso‐ventral and medio‐lateral shifting of the fibers from the dorsal roots as one goes from caudal segments to more cranial ones.A bilateral projection is demonstrated in the nucleus gracilis after section of nearly all the coccygeal‐sacro‐lumbar‐thoracic roots; the contralateral degeneration is confined to the rostral pole of the nucleus gracilis. No bilateral degeneration is found in the nucleus cuneatus after section of the roots projecting to it. Degenerated axons in the nucleus cuneatus lateralis and in the lateral reticular nucleus are always present beginning from T6–T7 while in the descending root of the fifth cranial nerve they are recognizable in only one case with a section of the third sacral root.
The facial outflow and the superior salivatory nucleus: An histochemical study in the rat
Authors: Brown J. Clevedon , Howlett B. 
Published: January 2005

AbstractShute and Lewis ('60) presented the first definite evidence for the localization of the superior salivatory nucleus by means of the thiocholine method for demonstrating cholinestrase. The outflow from this nucleus postulated by these workers is questionable in the light of other observations (Brown, '64). A re‐investigation of the salivatory nuclei in the rat by the thiocholine method in conjunction with three‐dimensional reconstructions shows that two topographically related cholinesterasepositive pathways are present at facial levels. These are the visceral motor (salivatory) rootlets and the olivo‐cochlear tract. The reconstructions decisively indicate a typical visceral motor outflow to the nervus intermedius from the superior salivatory nucleus and endorse Rasmussen's description of the olivo‐cochlear tract.
Autoradiographic study of histogenesis in the mouse olfactory bulb. II. Cell proliferation and migration
Authors: Hinds James W. 
Published: January 2005

AbstractCell proliferation and migration in the developing mouse olfactory bulb was studied by autoradiography. Animals were injected with thymidine‐H3 at various developmental stages and killed one to 96 hours later. All neurons arise in the germinal zone surrounding the ventricle. Until the fourteenth day of gestation (E14) this zone consists only of a matrix (primitive ependymal) layer. From E14 to E17 both matrix and subependymal layers are found, and from E18 to maturity only the subependymal layer is present. The matrix layer produces the mitral cells and some tufted and granule cells; the subependymal layer gives origin to some tufted cells and most of the granule cells. Mitral cell neuroblasts migrate peripherally to reach the primitive mitral cell layer three days after final DNA synthesis. Tufted cell neuroblasts migrate through the developing mitral cell layer to reach their definitive locations; external granule cell neuroblasts migrate past both developing mitral and tufted cells. Neuroglia arise from scattered proliferating glioblasts, originally derived from the periventricular germinal zone. Time of origin and rate of migration of olfactory bulb neurons was checked against the histological development of the bulb. A good agreement corroborated the autoradiographic method used in this study and in previous studies on time of origin of neurons in the central nervous system.
Correlation of glial proliferation with age in the mouse brain
Authors: Dalton Mary Margaret , Hommes O. R. , Leblond C. P. 
Published: January 2005

AbstractRadioautographs of brain sections were prepared after injection of 3H‐thymidine into mice aged 23, 100, 200 or 400 days.The presence of a small number of labeled cells in all animals indicates that neuroglia do proliferate even at an advanced age. Proliferation is most active in the corpus callosum and least so in the corpus striatum.Comparison of the counts of labeled and unlabeled nuclei suggests that glial cells are produced in numbers exceeding growth requirements and, accordingly, that they turn over, although slowly.
Some intrinsic connections of the hippocampus in the rat: An experimental analysis
Authors: Hjorth‐Simonsen A. 
Published: January 2005

AbstractSome internal pathways of the hippocampus were mapped in adult rats using Fink‐Heimer silver impregnation methods for the demonstration of anterograde axon degeneration.Cases with lesions of regio superior of the Ammon's horn showed that regio superior projects onto the subiculum by way of fibers in the alveus. The termination is most dense in the portion of the subiculum near the presubiculum. The fibers exhibit an orderly arrangement, in that the dorso‐ventral level of the subicular degeneration depends on the level of the regio‐superior lesion.No evidence of connections from regio superior to regio inferior and area dentata appeared in this study.The terminal fields of ipsilateral fibers from regio inferior to regio inferior and superior are pervaded by commissural fibers. This precludes selective destruction of the ipsilateral fibers in normal rats. In order to investigate these latter ipsilateral fibers, special animals were used in which the commissures had been transsected at the age of eight days. Secondary lesions were made in the hippocampus of the adults when no stainable commissural degeneration was demonstrable. The results obtained from these animals were the following.Lesions of regio inferior cause degeneration both in this subfield and in regio superior. The fibers terminate in the stratum oriens and radiatum, and not in the stratum lacunosum‐moleculare or on pyramidal cell bodies. The total spread of fibers along the longitudinal axis of the hippocampus is 4–5 mm, being slightly less in the regio inferior than in the regio superior. When the lesion involves only the dentate area and the adjacent part of the regio inferior, the degeneration in the regio superior is most pronounced superficially in the stratum radiatum and is absent from the stratum oriens. The fibers remaining within the regio inferior have a special mode of termination: dorsal to the lesion, degeneration is present in the deeper half of the stratum radiatum and in the stratum oriens; ventral to the lesion, degeneration is found predominantly in the superficial one half of the stratum radiatum.
An ultrastructural study of the effects of hypophysectomy on the supraoptic nucleus of the rat
Authors: Raisman G. 
Published: January 2005

AbstractThe axons of the supraoptic neurons of the rat were sectioned by means of a hypophysectomy. A minority of the neurons survive this operation apparently indefinitely. These cells show an initial stage of accumulation of neurosecretory material. After the first few weeks, the remaining neurohypophysial tissue becomes reorganised into a “miniature” neural lobe so that the neurosecretory cells acquire a new channel for the release of their material into the blood stream. The transient diabetes insipids subsides, and the surviving neurons undergo considerable hypertrophy. The majority of the supraoptic neurons disappear over the first few months after operation. During the first two weeks postoperatively degenerating neurons are found. They are shrunken cells with electron dense cytoplasm and show various stages of degradation of intracellular organelles. They are ultimately removed by the phagocytic activity of glial and possibly other cells.
Synaptic reorganization in the degenerating lateral geniculate nucleus of the rabbit
Authors: Ralston Henry J. , Chow Kao Liang 
Published: January 2005

AbstractAn investigation of synaptic plasticity in the lateral geniculate nucleus has been carried out in rabbits surviving one day to one year following ipsilateral visual cortex removal. There is extensive retrograde degeneration of LGN neurons, and the altered nucleus thus provides a model for examining reorganization of optic tract axons which have been deprived of their normal postsynaptic membrane.The distribution of synaptic contacts in normal LGN was quantitatively determined. In the animals surviving 1–14 days after cortex ablation, there was extensive cell death and loss of the axodendritic synapses of cortical origin, which constitute the most numerous synaptic type in normal LGN.In animals surviving 4–12 months, there were few remaining neurons and dendrites. The fine structure of the nucleus was characterized by a shift from axodendritic synaptic contacts, as in the normal, to a ten–fold increase in axoaxonal synapses, which became the dominant population. The contribution of optic axons to this synaptic population was determined by contralateral retinal removal. It was found that the synaptic axoaxonal organization in the altered LGN follows the rules of normal organization, in that optic afferents are invariably the presynaptic component in round to flat vesicle axoaxonal synapses.The LGN's undergoing chronic retrograde degeneration shrank to about twothirds the size of the normal nucleus. There was no evidence of reduction in the length of optic tract axons within the nucleus.The evidence indicates that there are new synaptic contacts formed between surviving axons in the degenerating LGN, as a consequence of the loss of postsynaptic dendritic membrane. The new synapse formation is guided by the normal rules of axoaxonal organization, indicating a maintenance of recognition of appropriate membrane for synaptic contact in the reordered LGN. It cannot be stated whether sprouting of axons accompanies the formation of new synapses or whether the new synaptic contacts are exclusively between preexisting synaptic knobs in LGN.
An ultrastructural analysis of the photoreceptors of the squid and their synaptic connections. I. Photoreceptive and non‐synaptic regions of the retina
Authors: Cohen Adolph I. 
Published: January 2005

AbstractAs part of a larger ultrastructural study on the photoreceptors of the squid,Loligo pealei, this paper reports findings on non‐synaptic regions. The cross‐sectional profiles of individual distal segments coincided in horizontal sections as far as 75 μ apart, but progressively less with greater separations. Areas of cross‐section showed a unimodal distribution skewed towards 6 μ2, the smallest areas. The distribution of ratios of villous to smooth border was unimodal and skewed with 1.0 being the most numerous and minimal ratio. This ratio tended to increase linearly with area. Cells of small cross‐section were completely surrounded by villous border of other cells and about 60° of the perimeter of any cell had microvilli on both sides of the border. Cells participated in odd or even numbers of rhabdomes, up to eight. Pentalaminar membrane junctions between microvilli of the same or neighboring cells were observed. Cytoplasmic microtubules were concentrated near villous borders. In light adaptation some ommin granules entered the photoreceptor tips, and the rhabdomes which formerly began near the surface, now began somewhat below this level. A terminal bar zone existed proximal to the rhabdomes. Here glial cytoplasm separated photoreceptors and both cells contained ommin granules. Photoreceptor somas lacked glial separation and were highly interplicated. Mitochondria were longitudinally arranged along the somal membrane. The planes of the lamellate membrane bodies, seen in the somal cytoplasm of the cells, did not exhibit a rectilinear pattern such as that displayed by the basically rectangular distal segment cross‐sections and microvillar orientations.
Projections from the parietal cortex to the brain stem nuclei in the cat, with special reference to the parietal cerebro‐cerebellar system
Authors: Mizuno Noboru , Mochizuki Kaori , Matsushima Chihiro Akimoto Ryotaro , Sasaki Kazuo 
Published: January 2005

AbstractDirect projections from the anterior portions of the parietal cortex of the cat to the brain stem nuclei, especially those sending fibers to the cerebellum, were investigated by the Nauta‐Gygax and Fink‐Heimer methods.Following unilateral lesions of the anterior portions of the middle suprasylvian and/or lateral gyri, a significant amount of pericellular degeneration was found almost entirely ipsilaterally in the rostral levels of the red nucleus and its vicinities, and in the pontine nuclei. Projection fibers to the pontine nuclei appeared to extend over several longitudinal, columnar zones in the pontine gray. Fibers from the anterior portion of the lateral gyrus were observed mainly in the paramedian and lateral nuclei, and those from the middle suprasylvian gyrus in the ventral, paramedian and lateral nuclei. Degeneration in the nucleus reticularis tegmenti pontis of Bechterew was slight, and found bilaterally with ipsilateral predominance.The significance of the anterior portion of the parietal cortex of the cat as a link of cerebro‐cerebellar loops was discussed.
Age changes in conduction velocity of unmyelinated fibers
Authors: Hopkins A. P. , Lambert E. H. 
Published: January 2005

AbstractIncrease of conduction velocity of unmyelinated fibers has been measured in the cervical sympathetic trunk of growing rats. Fibers in this nerve are almost all unmyelinated.
Conduction velocity is about half adult values at ten days after birth. The velocity in some nerves reaches the adult range by 50–80 days. There is evidence that the velocity of many fibers other than the fastest also reaches the adult range by this age.
During the period of growth from 10–112 days of age, velocity increases in direct proportion to the increase in length of the nerve.