bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cytoplasmic basophilia in the nerve cells of the cerebral cortex. VI. The human temporal cortex
Authors: Pakkenberg Henning 
Published: January 2005

AbstractAn attempt is made to evaluate the metabolic functional pattern in the nerve cells of a human temporal lobe by determining the cytoplasmic basophilia. Following gallocyanin staining (RNA staining), the extinction is measured at two points in each cell by means of a cytophotometer at 570 nm. The section thickness is determined, and measurements are made only on those cells which are known with certainty to be cut in both section surfaces. A total of 2000 cells is measured, distributed throughout five sites over the temporal lobe. In each layer, mean extinction values are found which do not deviate significantly from each other in the regions measured. The results are compared with previous findings from the frontal lobe of the same brain, and the conclusion is reached that the distribution of chromophobic, chromophilic and chromoneutral cells must be taken as expressing the fact that a majority of cells are in moderate activity, and that two small groups are in a somewhat greater metabolic activity. The distribution pattern is the same in different regions of the isocortex, possibly a result of the intimate communications characteristic of the cerebral cortex.
Observations on the ultrastructure of the developing cerebellum of the Macaca mulatta
Authors: Kornguth Steven Edward , Anderson John Walberg , Scott Grayson 
Published: January 2005

AbstractThe fine structure of the cerebellar cortex of the macaque fetus was examined at 75, 100, 125, 150, and 175 days after conception. Young Purkinje cells were recognizable in the 75 and 100‐day old fetuses, occurring in clusters several layers deep. The rough endoplasmic reticulum in the Purkinje cells was limited to the perinuclear area and the region of apical cytoplasm adjacent to the plasmalemma. Neither dendritic processes nor synaptic contacts were seen on Purkinje cells at this time, although an occasional observation was made of synapses involving other cell types. Between 100 and 125 days, the cerebellar cortex matured rapidly. At the latter time, the Purkinje cells had a well developed dendrite, and axodendritic and axosomatic synapses were seen. At 150 days gestation age the Purkinje cells had well developed Nissl substance, and the axodendritic synapses were similar in structure to the adult spine contact. The relationship between maturation of the thyroid gland and of the cerebellum in the macaque is discussed.
Relation between the number of myelin lamellae and axon circumference in fibers of vagus and sciatic nerves of mice
Authors: Friede Reinhard L. , Samorajski T. 
Published: January 2005

AbstractNerve fiber populations of the vagus and sciatic nerves of mice were classified according to the number of myelin lamellae present in the sheaths. This method for classifying fiber populations was superior to others used previously since it provided a more sensitive procedure for the analysis of individual fibers and better control over the technical factors involved in tissue processing.The relationship of the number of myelin lamellae in the sheath to axon circumference was found to be linear. In fresh tissue there was one myelin lamella for every 0.24 μ increase in axon circumference above da value of 2.32 μ (the mean circumference of an average‐sized nonmyelinated fiber). A formula was proposed which may be useful for understanding how axons control myelin development and interpreting developmental stages, as well as for evaluating pathologic conditions affecting the peripheral nervous system.The critical diameter above which fibers were found to be myelinated was about 0.8 μ for fixed nerve and 1.1 μ for fresh nerve. The ratio of axon diameter to fiber diameter ranged between 0.5 and 0.9 and was not related to fiber size.
The postnatal development of the spinal cord of the dog
Authors: Fox Michael W. , Inman Ottilie R. , Himwich Williamina A. 
Published: January 2005

AbstractThe postnatal myelinization of the dorsal, lateral and vertral funiculi in the spinal cord of the dog occurs rapidly during the first three weeks of life, with the exception of the fasciculus gracilis and lateral corticospinal tract in which myelin is not complete until after five weeks. The ventral (motor) grey columns are more developed in younger animals than the corresponding dorsal columns. Both ventral and dorsal columns reach adult form by five weeks of age, but the lateral columns mature later. Only slight morphological differences were found in the rate of development of cervical and lumbar segments, the latter maturing a little later. These findings are compared with earlier studies in the cat, and correlated with observations on reflex and locomotor development of the dog.
Experimental study of the projections of the nucleus of the tractus solitarius and the area postrema in the cat
Authors: Morest D. Kent 
Published: January 2005

AbstractProjections from the area postrema and adjacent parts of the medial solitary nucleus are demonstrated with the Nauta method following lesions limited exclusively to these structures. Experiments are controlled with lesions involving adjacent bulbar regions, cerebellum, and spinal cord. Ascending pathways in the dorsal and lateral columns of the spinal cord project ipsilaterally to the area postrema and bilaterally to a para‐alar nucleus in the ventral periphery of the nucleus gracilis. Neurons in the area postrema project mainly inspilaterally to the dorsal and medial regions of the medial solitary nucleus. Neurons in the posterior half of the medical solitary nucleus project ipsilaterally to the lateral solitary nucleus, dorsal vagal nucleus, ambigus, retrofacial nucleus, and dorsal and lateral bulbar reticular formation. Projections to nuclei intercalatus and prepositus hypoglossi, bilaterally, and to the ipsilateral dorsal tegmental nucleus by way of the dorsal longitudinal fasciculus are also shown. No direct projections to the diencephalon are demonstrated. Control lesions in the dorsal column nuclei reveal projections to the contralateral inferior olive and thalamic reticular and ventrobasal nuclei, but not to the projection sites of the solitary nucleus. Evidence is given to support the hypothesis that ascening visceral pathways are interruped in the bulbar reticular formation and dorsal tegmental nucleus before reaching the diencephalon. Correlations are suggested with functional aspects of the central autonomic and reticular activating systems.
Thalamic afferents from the spinal cord and trigeminal nuclei. An experimental anatomical study in the rat.
Authors: Lund R. D. , Webster K. E. 
Published: January 2005

AbstractDegeneration studies after making lesions involving the spino‐thalamic pathways indicate that the projection from any level of the cord to the ventrobasal complex differs from that of the medial lemniscus in that it is less dense and ends largely in the rostral one third in a topographical pattern. Additional projections from all levels of the cord end in the nuclei pretectalis anterior, centralis lateralis, medialis dorsalis and in the medial geniculate body pars medialis and dorsal part of the posterolateral complex. Fibers from the rostral few segments of the cord, possibly from the lateral cervical nucleus, end in addition in the caudal part of the ventrobasal complex and sparsely in the parafascicular‐centrum medianum complex and zona incerta. Heavy degeneration was found in all the brains in the brainstem reticular formation.The tritgeminal sensory nuclei project heavily to the dorsomedial cell band of the ventrobasal complex and sparsely to the neighboring part of the posterolateral complex. There is no evidence of a projection from any level of the trigeminal sensory complex to any part of the intralaminar nuclei.
Somatotopic organization in the spinal trigeminal nucleus, the dorsal column nuclei and related structures in the rat
Authors: Nord Samuel G. 
Published: January 2005

AbstractThe medulla of the anesthetized rat was explored with with fine (25.4 μ) wire electrodes from C1 rostrally to the cerebellar penduncles. Concurrently, the body surface and the buccal cavity were mechanically stimulated with delicate probes. Descriptions of peripheral fields and characteristics of evoked discharges were recorded. Histological evidence revealed that the dorsal column nuclei yeilded responses to stimulation of the limbs, trunk, posterior face and pinna. The spinal trigeminal nucleus indicated an input from the face and from buccal cavity components, while the solitary nucleus disclosed an input originating in the tongue and, less often, in other oral structures. In addition, loci in adjacent portions of the reticular formation gave responses to mild stimulation of many peripheral regions. Most of the body projected to every level of the medulla studied. The projection was typically homolateral, and fields of many sizes were represented throughout the longitudinal extent of each nucleus. The amount of bulbar tissue devoted to any region of the body appeared to be related to the innervation density of that region. The results support the concept that the nuclei can be regarded together as a functional unit which resembles the primary tactile systems of the thalamus and the cortex in somatotopic organization.
Topography and numerical distribution of intracardiac ganglion cells in the cat
Authors: Calaresu Franco R. , Louis Arthur J. St. 
Published: January 2005

AbstractSerial sections stained with thionin and with phosphotungstic acid hematoxylin of a complete kitten heart and of portions of hearts from eight adult cats were studied to determine the location of intracardiac ganglion cells and to estimate their number. Ganglion cells were found in well defined anatomical relationships to the great vessels, the atria and the interatrial septum, but were never found below the coronary sulcus. Several distinct groups are described. The estimated total number of ganglion cells in an adult heart is 8405. Histological relationships between ganglion cell groups and nodal tissue, coronary arteries and myocardial tissue are described.
Fine structure of sensory ganglion cells during limb regeneration of the newt Triturus
Authors: Lentz Thomas L. 
Published: January 2005

AbstractThe regeneration of the limb of the newt depends upon the nervous system. The fine structure of sensory ganglion cells of the newt Triturus viridescens was studied during limb regeneration to determine whether any changes could be associated with trophic function. Several changes were noted in the cell bodies following amputation of the limb. Lipofuscin pigment bodies are greatly increased in number. Some cells contain giant mitochondria with a diameter of 2 μ and others contain clusters of many small mitochondria. Small Golgi complexes occur in close proximity to the giant mitochondria. Dense membrane‐bounded granules, not observed normally, with a diameter of ∼ 1000A occur in the region of these Golgi complexes. The endoplasmic reticulum becomes more dispersed during regeneration while the ratio of free to attached ribosomes increases. Some cells show extensive chromatolytic changes consisting of dissolution of the endoplasmic reticulum.The structural changes are discussed in relation to the trophic action of nerves and regeneration of the nerve fiber. Changes in lipofuscin granules and mitochondria may be indicative of increased oxidative metabolic activity. The changes in the endoplasmic reticulum and ribosomes are suggestive of a reorganization of the protein synthetic machinery of the cell. The appearance of dense granules in the perikaryon coincides with the accumulation of granules in the peripheral regenerating nerves. These structures may be associated with the formation, transport, and release of a possible trophic substance or hormone.
Comparative electrophysiological studies on the olfactory tract of some teleosts
Authors: Døving Kjell B. 
Published: January 2005

AbstractThe compound action potential was recorded from the olfactory tract of seven species of the teleost orders Anacathini and ostariophysi. In all species examined three components were found with peak velocities in the ranges of 0.8–4.3, 0.5–2.3 and 0.13–0.22 msec−1 for the first, second and third component respectively. The third component was comparatively large and was always present in the medial bundle of the tract, but in the species of Ostariophysi this component was also presnet in the lateral bundle. One of the examined species, Raniceps raninus, had sessile bulbs and not, as previously reported, long olfactory stalks. The maximum rate of conduction of the olfactory nerve in this species was found to be 0.12 msec−1 at 10°C.
On the probable absense of retino‐hypothalamic connections in five mammals and an amphibian
Authors: Kiernan John Alan 
Published: January 2005

AbstractAttempts have been made in the Rat, Rabbit, Hedgehog, Ferret and Xenopus toad to trace degenerating fibers into the hypothalamus after division of one optic nerve. No evidence was found of a retion‐hypothalamic connection. This finding is not in accordance with the results reported by several others who made comparable experiments; and it is suggested that confusion may have arisen because neuro‐secretory nerve fibers taken for degenerating hypothalamic pathways.
The development of hippocampal and dorsolateral pallial regions of the cerebral hemisphere in fetal rabbits IV. Forty‐one millimeter stage, intermediate lamina
Authors: Stensaas L. J. 
Published: January 2005

AbstractThe structure of the cerebral hemisphere of the 41 mm rabbit embroy was studied with aniline and Golgi stains. Special attention was devoted to the intermediate lamina which forms the embryonic subcortical white matter. From Golgi preparations, two facts suggest that a simple plan underlies the distribution of most axons in this lamina: (1) axons of neuroblasts in the matrix and intermediate laminae turn in the lower part of this layer; (2) axons of neurons near the base of the cortical plate turn in the upper part of it. Since neuroblasts in the matrix and intermediate laminae are younger than cells forming the cortical plate, it is inferred that increments of growth occur along the lower surface of the intermediate lamina by the addition of new fibers. the factors which effect the growth of axons is not known, but it is possible that growth cones of some neuroblasts are guided through contact with previously formed horizontal fibers of this layer.
The basal ganglia of Testudo Graeca
Authors: Hewitt W. 
Published: January 2005

AbstractThe basal ganglia of Testudo Graeca consist of upper and lower elevations in the side wall of the cerebral hemisphere. In the lower elevation is the medial forebrain bundle, and its hypothalamic connections suggest it may be concerned with visceral activities. In the upper elevation is the lateral forebrain bundle suggesting its connections are thalamic, and from experimental material there is little evidence that any are olfactory. The cells of the outer part of the lower elevation form a curved lamina pierced by the lateral forebrain bundle, resembling the formation of the human lentiform nucleus and internal capsule.Between the dorsal cortex and lower elevation or further caudally the upper elevation, is a curved band of cells, continuous with the upper end of the piriform cortex, which has been called the pallial thickening. It is suggested that this represents the outer of the three elevations forming the developing human caudate nucleus. Transecting this are fibers connecting the cortex and lateral forebrain bundle, and it is proposed that the entire length of these fibers is equivalent to part of the human internal capsule.
Histochemical studies on the accessory body of Cajal in neurones of the cat
Authors: Nayyar Rajan P. , Barr Murray L. 
Published: January 2005

AbstractThe accessory body of Cajal is an argyrophil body measuring between 0.5 μ and 1.0 μ in diameter and is present in the nuclei of most neurones of the cat. Histochemically, the accessory body contains small amounts of bound lipids and proteins containing tyrosine, NH2 groups and arginine. It does not possess detectable amounts of nucleic acids (RNA or DNA), tryptophan, histidine or amino acids with free SH groups. The accessory body of Cajal differs from the sex chromatin and the nucleolus in several important respects. Its role in cellular physiology is unknown.
Some fine structural features of the neural elements composing the cerebellar nuclei in the cat
Authors: Eager Robert P. 
Published: January 2005

AbstractAll cerebellar nuclear areas examined contained neurons of several sizes. The smallest have cell bodies ranging from 8–15 μ in diameter in which the cytoplasm is sparse and the granular endoplasmic reticulum randomly distributed. The larger neurons range in diameter from 25–40 μ and the granular reticulum is highly organized and forms Nissl bodies.Axo‐somatic terminals occur on all neurons seen in the cerebellar nuclei but are randomly distributed and not usually juxtaposed on the cell surface. Several types of axo‐dendritic terminals were encountered. Those on small dendritic branches are characterized by asymmetric accumulations of electron dense material in the postsynaptic cytoplasm. They are also usually bounded by astrocytic glial processes. Terminals on large dendrites show long lengths of membrane apposition and discontinuity of synaptic contacts. A number of dendrites displayed spines upon which terminations occurred. Terminal boutons were also observed to arise from nodes of Ranvier.The neuropil surrounding the neurons of the cerebellar nuclei is filled with myelinated fibers of varying diameter, the smallest of which are about 0.4 μ. The latter often occupy positions close to the surface of neuronal cell bodies and dendrites. Only few unmyelinated fibers were observed.
The fine structure of neurons in the dorsal horn of the cat spinal cord
Authors: Ralston Henry J. 
Published: January 2005

AbstractThe fine structure of the dorsal horn of the cat cord has been compared with the light microscope cytoarchitectural studies. Several distinct laminae may be seen with the electron microscope. Lamina I contains marginal cells of Waldeyer and has its processes oriented in a horizontal direction. Lamina II contains small neurons and processes oriented vertically, and may be distinguished from lamina III by the rich content of myelinated axons in the latter. In laminae I–III there are numerous non‐myelinated axons and many axodendritic and axoaxonal synapses but few axosomatic ones. Complex synaptic arrays made up of a central axon synapsing with other axons and dendrites are commonly seen.Laminae IV, V and VI are distinguished by their content of large neurons. They exhibit many axodendritic and axosomatic synapses but few axoaxonal ones and no complex synaptic arrays. Synaptic knobs containing rings of neurofilaments are present only in laminae IV–VI and synapse usually with somata or dendrites of neurons. There are differences in synaptic vesicle configuration and in the density of subsynaptic membranes associated with them.Differentiation of the dorsal horn into horizontal laminae is demonstrated by both light and electron microscope studies. The regional differences in neuronal organization may represent differences in functional organization as well.
Dorsal root projections to dorsal horn neurons in the cat spinal cord
Authors: Ralston Henry J. 
Published: January 2005

AbstractThe projection of dorsal root fibers to the dorsal horn of the spinal cord of the cat has been studied by electron microscopy. Two distinct types of synaptic degeneration are seen with the electron microscope: small knobs which exhibit a marked increase in electron density, and large knobs which fill with neurofilaments. Variations in the distribution of degenerating knobs to the six laminae of the dorsal horn are observed: dense degenerating knobs are found throughout the horn, but are quite rare in laminae I and II. Lamina III exhibits the most dense knobs, and a great many are also present in laminae IV and VI with a somewhat lesser number seen in lamina V. Knobs undergoing neurofilamentous degeneration are found only in laminae V and VI, and are much Jess frequently seen than are dense knobs.The types of synaptic contacts made by degenerating dorsal root fibers also vary from one region of the dorsal horn to another. Dense degenerating knobs synapse primarily with small dendrites in laminae I, II and III, but not at all with large dendrites or nerve cell bodies. In lamina III, dense knobs are seen in axoaxonal synapses, and are always the pre‐synaptic component of the synapse. In laminae IV, V and VI dark knobs are commonly seen to synapse upon cell bodies of large and medium sized neurons and their proximal dendrites, but not upon small cell bodies Dense knobs upon small dendrites are common. In degenerating axoaxonal synapses, the dense knob is always the post‐synaptic component.Degenerating neurofibrillar knobs are only seen to synapse with cell bodies or larger dendrites in V and VI and not at all other synaptic knobs.The results are correlated with findings by light microscopy. Comparisons are made with some of the known physiological properties of dorsal horn neurons.
Quantitative data on the inferior olivary nucleus in man, cat and vampire bat
Authors: Escobar Alfonso , Sampedro Elia D. , Dow Robert S. 
Published: January 2005

AbstractA quantitative study of the inferior olivary nucleus in single specimens of man, cat and vampire bat has been made. The number of cells in the human is about 908,680 which is about one‐fifteenth the number of Purkinje cells thought by others to be present in the human cerebellum.The estimated figure in the cat is about 140,520 while in the vampire it is 26,644. The relation of these figures to the total number of Purkinje cells in the last two species is still to be determined. The neuron density is highest in the vampire where the volume of the cell bodies represents one‐eighth the total volume of the nucleus while in the cat the comparable ratio is one‐sixteenth, and in the human one‐twenty‐fifth. This reflects the richer neuropils of afferent connections and dendrites in the more highly developed species.Unsolved problems and discrepancies concerning the number of olivary cells and Purkinje cells in the light of present concepts of the olivary origin of climbing fibers are discussed and areas of future study are suggested.
Transcortical striate connections in the opossum
Authors: Kunze Diana L. , Putnam Serpas J. , Manning John W. 
Published: January 2005

AbstractExtracellular unit responses to transcortical stimulus confirm striate to striate connections in the opossum. The presence of short latency fiber responses and antidromically activated cells indicate that these connections are direct. Responding units were located over all of the dorsal surface with the exception of small mediocaudal area. The depth of location corresponded to layers two through six of the striate cortex. A lack of correlation between the depth of location and the latency of firing indicates that the incoming fibers are distributed to all layers with the exception of layer one. Units were located which responded to both a transcortical stimulus and a flash of light presented to the contralateral eye. These interacting units were localized to a discrete position of the striate area. This arrangement presents a possible mechanism of tying the visual fields together in the binocular area and allowing continuity between the left and right visual fields.