bluuebunny/crossref_metadata_2025_split huggingface dataset:
A simple method for determining cerebralization. Brain weight and intelligence
Authors: Krompecher S. T. , Lipák J. 
Published: January 2005

AbstractBy means of comparing the weight of the brain with the weight of the spinal cord the authors seek a way to appraise the intelligence of the individual. Authors' concept, on the one hand, unites the advantages of the other methods, on the other hand, it reduces their errors. Namely, the weight of the spinal cord stands in proportion to the bulk of the body of the individual, its surface and its functions, while the brain — with the exception of a small somatic part standing in constant correlation with the spinal cord — serves as the seat of the intellect. In different vertebrates the weight of the brain surpasses that of the spinal cord in different degrees. The weight of the brain in the frog is twice as high as that of its spinal cord, in the dog six times, in the cerkof monkey 14 times, in the orang‐utan 33 times, and in man 43 times. Pertinent detailed data are revealed by the table.
The localization, in the nucleus ambiguus of the rabbit, of the cells of origin of motor nerve fibers in the glossopharyngeal nerve and various branches of the vagus nerve by means of retrograde degeneration
Authors: Lawn A. M. 
Published: January 2005

AbstractThe glossopharyngeal nerve and the vagus nerve or its branches were cut individually or in various combinations in different rabbits. In two animals the cricothyroid muscle of the larynx was dissected away. The distribution in the nucleus ambiguus of the neurons of origin of motor fibers in the various nerve branches was deduced from the retrograde degeneration observed in these cells after the appropriate branch had been cut or muscle had been removed. The part of the glossopharyngeal nerve associated with the nucleus ambiguus was found to arise from a compact mass of cells lying level with, but ventrolateral to, the rostral tip of the principal column of the nucleus, forming the rostral extremity of the medial column. The remainder of the medial column was shown to give rise to axons innervating the cricothyroid muscle. The principal column contains a group of cells innvervating the pharynx and soft palate and a group innervating the esophagus, but there was considerable rostrocaudal overlap between these two groups. Some evidence is presented showing that the cells for the cervical esophagus are not clearly separated rostrocaudally from the cells for the abdominal esophagus. The cells of the diffuse formation innervate the intrinsic muscles of the larynx excepting the cricothyroid muscle.
Patterns of form and function in the central nervous system of Ariolimax
Authors: Turner R. S. 
Published: January 2005

AbstractThe external and internal morphology of the central nervous system of the large terrestrial gastropod Ariolimax columbianus are shown to be typical of the general pattern for stylommatophoran pulmonates. This typicality recommends Ariolimax as a useful normal model for experimental investigation of the molluscan nervous system. The central nervous system of this form was reconstructed by tracing every section of a horizontally serially sectioned specimen onto transparent acetate tracing film at a magnification of 32 ×. The position of all cells greater than 50 m̈ in diameter as well as the locations of neuropil, septa, exits of the various nerves, etc., were all carefully indicated on this model. By comparing sections serially cut in different planes with the reconstruction it becomes apparent that many, if not most, of the larger cells and constellations of cells are identifiable from animal to animal. This finding is consistent with the assumption that basic stereotyped responses most probably reflect stereotyped anatomical patterns. Fixed neuronal patterns in turn suggest basic identifiable discharge patterns over the major nervous pathways. By double beam recording it is demonstrated that recognizable “core discharge” patterns from the central nervous system can indeed be distinguished following various controlled afferent inputs. The results of this study support the concept of a physiologically and anatomically patterned, as opposed to a randomly functioning, neuropil.
Electron microscopic studies of the dentate gyrus of the rat. I. Normal structure with special reference to synaptic organization
Authors: Laatsch R. H. , Cowan W. M. 
Published: January 2005

AbstractThe fine structure of the dentate gyrus of the rat has been studied in glutaraldehyde perfused material. With the exception of the short axon association cells, the major components of each of the three layers of the gyrus have been identified, and a detailed account is given of the synaptic organization of the dentate granule cells.The granule cells have most of the features typical of small neurons and although they contain no large aggregates of granular endoplasmic reticular they exhibit a variety of cisternal specializations. In the granule cell layer numerous axo‐somatic and axo‐dendritic synapses have been observed, and on occasion a single presynaptic fiber has been seen to contact the soma of one cell and a proximal dendrite of another. In the inner part of the molecular layer the majority of synapses are upon the main dendritic shafts of the granule cells but many also contact short dendritic spines. In the outer two‐thirds of this layer most presynaptic fibers end upon long dendritic spines some of which are characterized by a prominent projection from the subsynaptic surface into the presynaptic process. The unmyelinated axons of the granule cells establish many en passant contacts with dendrites and spines of CA4 pyramids before ending in large presynaptic bags which may contain a number of large agranular vesicles (up to 2,000 Å in diameter) and vesicles with dense cores.
The lateral cervical nucleus of the Japanese monkey (Macaca fuscata)
Authors: Mizuno Noboru , Nakano Katsuma , Imaizumi Masamichi , Okamoto Michio 
Published: January 2005

AbstractBased on the normal histological findings and the organization of the spinal afferents revealed by the Nauta and the Marchi methods, a cell group corresponding to the lateral cervical nucleus (NCL) of the cat was identified in the first and the second cervical segments of the spinal cord of the Japanese monkey (Macaca fuscata).The nucleus begins to appear at the level of the caudal end of the gracile nucleus and gradually disappears within the caudal half of the second cervical segment of the cord. The nucleus consists of medium‐sized and small‐sized nerve cells and receives spinal afferents ascending through the lateral funiculus, probably chiefly through the posterior spino‐cerebellar tract, from lower levels of the spinal cord. The spinal afferents seem to take origin entirely, or at least chiefly, from the ipsilateral spinal gray and to terminate in the nucleus without any localization. Some problems concerning the lateral cervical nucleus as the site of the spino‐thalamic tract have also been discussed from the point of view of comparative anatomy.
Electron microscopy of classically stained astrocytes
Authors: Vaughn James E. , Pease Daniel C. 
Published: January 2005

AbstractSections of cat cerebral cortex stained for astroytes by the Cajal gold chloride‐sublimate method have been examined with the electron microscope. Small, electron‐opaque dots representing gold deposition are specifically concentrated in cells which have swollen, clear perikaryal areas and processes which terminate as perivascular end feet. The appearance of these cells is very similar to the “watery” cells identified as astrocytes in some of the early electron microscopic investigations of central nervous tissue. Neurons and oligodendrocytes, in those layers of cortex examined electron microscopicallly, contain only a small number of gold particles.A possible morphological substrate explaining the sepecificity of the Cajal method for astrocytes is discussed.
Visual and non‐visual factors in the centripetal stimulation of postnatal growth of the visual centers in mice
Authors: Gyllensten Lars , Malmfors Torbjörn , Norrlin‐Grettve Marie‐Louise 
Published: January 2005

AbstractThe diameter of cell nuclei and mean volume of internuclear material per nucleus were determinated in the visual corte, lateral geniculate bodies and superior colliculi in growing mice. The influence of bilateral removal of the eyes at birth was studied, and compared with the effects of rearing the animals in complete darkness from birth.Bilateral removal of the eyes caused a decrease in nuclear size and relative voulme of internuclear material at two and four months after birth. Compared to similar changes in dark‐reared mice, the decreases were greater in the mice without eyes, particularly in the subcortical visual centers. After eye removal, no growth of nuclei and internuclear material was observed between two and four months of age. This is in contrast to the findings in dark‐reared mice, in which partial “normalization” occurred during prolonged stay in the dark betwen two and four months. It is concluded that the postnatal growth and differentiation of the visual centers are stimulated both by visual stimuli and by non‐visual stimuli from the optic nerve fibers.
Somatotopic organization of raccoon dorsal column nuclei
Authors: Johnson J. I. , Welker W. I. , Pubols B. H. 
Published: January 2005

AbstractSomatotopic organization was demonstrated by means of microelectrode mapping studies of three somatic sensory nuclear regions in the raccoon medulla.
Projections of peripheral receptive fields in the cuneate‐gracile nuclear complex occur iteratively in rostro‐caudal columns. These projections are organized into a detailed 3‐dimensional pattern, in contrast to the more diffuse intermingling of such projections in the spinal dorsal roots and columns. This indicates that afferent fibers are re‐sorted before synaptic termination. In the extensive representation of the volar hand, there are distinct subnuclei, delineated by intervening fiber laminae, each containing the projections from one of the forepaw digits.
Units in the external‐cuneate nucleus responded only to stimulation of deeperlying tissues in anterior body regions. These projections were also somatotopically organized. Retrograde degeneration studies indicated that some cells, in that region where cuneate‐gracile adjoins external‐cuneate, may project through both the ipsilateral cerebellar peduncles and the contralateral midbrain.
The spinal trigeminal nucleus adjoining the cuneate‐gracile complex displayed many characteristics similar to those of the latter.
Neighboring, although anatomically distinct, regions contained projections from neighboring peripheral receptive fields.
The development of hippocampal and dorsolateral pallial regions of the cerebral hemisphere in fetal rabbits. VI. Ninety millimeter stage, cortical differentiation
Authors: Stensaas L. J. 
Published: January 2005

AbstractThe structure of the cerebral hemisphere of 90 mm rabbit embryos was studied with aniline and Golgi stains and a comparison of cortical plate morphology was made with earlier stages. Neuronal differentiation was inferred to be a continuous process since cells forming the base of the cortical plate gradually increase in size from 29 mm through 90 mm stages. However, differentiation also appeared to be most rapid among cells situated near the marginal lamina. Analysis of the development of large pyramids of layer V in the pallial region provided the most convincing proof for this conclusion. This mode of cortical development suggests the possibility that embryonic synapses are estabilished sequentially along the apical dendrites of pyramidal cells as the cortical plate grows through the addition of new cells. This process is postulated to occur in a “critical zone” at the boundary of the marginal lamina with the cortical plate.The development of interneuronal neuropile in the lower part of the cortical plate of 90 mm embryos seems to be correlated not only with the growth of basal dendrites and axon collaterals, but also with the simultaneous appearance of true astrocytes and oligodendrocytes.
Development of fine structure of spinal cord in monkey fetuses. II. Pre‐reflex period to period of long intersegmental reflexes
Authors: Bodian David , Melby Edward C. , Taylor Naomi 
Published: January 2005

AbstractA series of 13 macaque fetuses of estimated ovulation ages 42 to 51 days (17 to 41 mm) was subjected to behavioral analysis with umbilical cord intact (in and out of the amnion), and to light and electron microscopic analysis of the cervical spinal cord. This period is a critical one in terms of onset and early development of spontaneous activity and of cutaneous reflexes. Behavioral criteria, reinforced by well‐defined microscopic characteristics, suggested a grouping of specimens into three major stages, namely, a pre‐reflex group (Stage 1: 17–22 mm); a group in the period of onset of primitive spontaneous activity and of precocious local cutaneous reflexes in the trigeminal‐cervical region (Stage 2: 24 to 28 mm); and a group characterized by the development of more vigorous activity, spontaneous and otherwise, and of long intersegmental and crossed reflexes (Stage 3: 32 to 41 mm). The evidence suggests that junctional differentiation and occurrance of a cluster of agranular spheroid synaptic vesicles characterize the primitive synaptic knobs which appear on motoneuron dendrites coincident with earliest reflexes. Onset of active long intersegmental reflexes in Stage 3 is coincident with development of axosomatic synaptic knobs, and of F type (flattened) synaptic vesicles in a rapidly increasing fraction of all synaptic bulbs in the motoneuron neuropil. Total volume of all synaptic bulbs increases gradually as a fraction of the volume of the motoneuron neuropil until birth, but a steep increase in proportionate number of F type synaptic knobs occurs in Stage 3.
A third neuroglial cell types. An electron microscopic study
Authors: Vaughan James E. , Peters Alan 
Published: January 2005

AbstractDuring a study of developing optic nerves, it was necessary to reevaluate the earlier electron microscopic evidence that only two neuroglial types, oligodendrocytes and fibrous astrocytes, are contained within central white matter. A reexamination of adult optic nerves showed that in addition to these two kinds of cells, a third morphologically distinct cell type exists. Cells of this third neuroglial variety are small and their cytoplasmic density is less than that of all forms of oligodendrocytes but slightly more than that of astrocytes. Neither the filaments and glycogen particles characteristic of astrocytes nor the microtubules typical of oligodendrocytes are observed in the third type of neuroglia. Dense, laminar bodies and fat droplets are frequently present within their cytoplasm, and profiles of the granular endoplasmic reticulum consist of long, stringy cisternae. Fetal and early postnatal optic nerves contain a cell type with the same morphological characteristics. This suggests that the third type of neuroglia in adult nerves may represent cells of a similar nature to the multipotential stem cells of other tissues. Some of the characteristics of the third type of neuroglia are reminiscent of the microglia of classical light microscopy, but data from developing nerves indicates that the former are derived from neuroectodermal matrix cells and not from invading mesenchymal elements.
Cholinesterases in the area subpostremas. A region adjacent to the area postrema in the cat
Authors: Gwyn David G. , Wolstencroft John H. 
Published: January 2005

AbstractA region in the medulla oblongata of the cat, which has been named the area subpostrema, has been described. This area is unique in demonstrating strong staining for both specific and pseudocholinesterase in the walls of capillaries and also in an arc of neuropil which partly surrounds these capillaries. Over most of its length the area subpostrema lies immediately ventral or ventrolateral to the area postrema, dorsal to the dorsal motor nucleus of the vagus and dorsomedial to the tractus solitarius. The area subpostrema, unlike the area postrema, is not stained by the vital dye trypan blue. A group of capillaries in the inferior olivary nucleus which demonstrate specific but not pseudocholinesterase activity have also been described.Using Nissl stains and silver impregnation techniques the area subpostrema has been found to contain a few small neurones and many unmyelinated nerve fibers. Some nerve fibers within the area subpostrema demonstrate specific cholinesterase activity.The relation of the area subpostrema to the nucleus of the tractus solitarius has been discussed. It has been suggested that the area subpostrema might have receptor functions related to autonomic control.
A study of fiber systems within the spinal cord of the domestic pig that subserve pain
Authors: Breazile James E. , Kitchell Ralph L. 
Published: January 2005

AbstractA total of 21 domestic pigs were used in a study of spinal cord fiber systems which subserve a pain response in the pig. Distribution of fiber systems were determined by the placement of various lesions into the spinal cord and examining the animal for its ability to give a complete pain response. The Swank‐Davenport modification of the Marchi technique for staining degenerating myelnated fibers was used to determine the pattern of trajectory of myelinated fibers along the spinal cord. Lesions were made at the cervical level in three animals and resulting pattern of degenerating fibers was compared with those of the other animals in which the lesions had been placed at lower thoracic levels. In most animals the lesions were limited to a single site on the spinal cord, but in six animals staggered, bilateral hemisections were made to determine whether or not these fiber systems are as diffuse in the pig as has been reported for the cat.The spinal cord fiber systems which subserve a pain response in the pig are located generally within the ventrolateral quadrant of the spinal cord. It was found that only a small portion of one lateral funiculus just ventral to the dorsal and ventral spinocerebellar tracts, if left intact, was sufficient for the elicitation of a pain response from either rear limb.The results presented here indicate that the fiber systems in the spinal cord of the pig which subserve pain responses are more diffuse than in carnivora or in primates.
Direct projections from the masseteric nerve to the mesencephalic nucleus
Authors: Smith R. Dale , Marcarian Heront Q. , Niemer William T. 
Published: January 2005

AbstractThe caliber spectrum of the nerve to the masseter muscle of the cat was found to be unimodal, ranging from 1 to 16 μ, with the majority of the fibers in the 4‐8 μ range. The upper 25%, which includes the afferent propriococoptive fibers, averaged 10.4 μ. The nerve to the masseter was stimulated and evoked potentials were recorded from the ipsi‐ and contralateral mesencephalic nuclei of the trigeminus and from the contralateral nerve. The average latencies were 0.846, 0.935 and 1.46 msec respectively. The mesencephalic nucleus was stimulated and evoked potentials were recorded from the contrlateral nucleus with an average latency of 0.385 msec. Analysis of the latencies of the responses recorded from the ipsilateral nucleus suggested that about half of the fibers of the nerve to the masster projected directly and the other half projected by way of an intervening synapse. A similar distribution of the fibers to the contralateral nucleus was deduced from the recorded latencies. Potentials recorded in the nuclei as a result of stimulation of the contralateral nucleus demonstrated that there were direct internuclear pathways without intervening synapses. The latencies of potentials recorded in the nerve as a result of stimulation of the contralateral nerve indicated that there was always at least one synapse intervening. It was also shown that there were direct projections from the nerve of the masseter to the contralateral motor nucleus of V. The work confirms our earlier report of bilateral projections from a muscle of mastication to the mesencephalic nuclei and provides a pathway for bilteral simultaneous activation of the muscles of mastication resulting from stimulation of unilateral tension receptors.
The frequency of occurrence of Barnes' ventrolateral pyramidal tract
Authors: Mizuno Noboru , Nakamura Yasuhisa , Okamoto Michio 
Published: January 2005

AbstractIn order to study the frequency of occurrence of Barnes' ventrolateral pyramidal tract, the lower parts of the medulla oblongata and the upper three cervical segments of the spinal cords of 210 adult Japanese were examined histologically.The tracts were encountered in 43 out of 210 cases (20.5 ± 2.8%); bilaterally in (7.6 ± 1.8%), and unilaterally in 27 (12.9 ± 2.3%) cases. Consequently the tracts were found to be present in 59 out of 420 sides (14.0 ± 1.7%). Sex diffierence was not statistically significant (χ2 = 0.6, d.f. = 1, p > 0.25).
Somatotopic organization of mechanoreceptor units in the trigeminal nuclear complex of the macaque
Authors: Kerfl F. W. L. , Kruger L. , Schwassmann H. O. , Stern R. 
Published: January 2005

AbstractThe properties of neurons in the sensory trigeminal nuclear complex of macaque monkeys have been investigated by a systematic exploration of the principal sub‐divisions in an attempt to define somatotopic organization, modality representation, receptive field size and adaptive properties. Particular attention was paid to several discrepancies in the literature on the cat trigeminal complex. The results suggest that each cutaneous locus is represented by a rostro‐caudally oriented column of neurons possessing comparable properties and receptive field sizes at all levels examined in deeply anesthetized animals. A consistent somatotopic pattern with minor variations, was evident at all rostro‐caudal levels. Criteria for distinguishing “spinothalmic” and “lemniscal” neuron properties in appropriate portions of the sensory complex (inferred from human data) could not be identified. Neurons in adjacent structures may respond to crude stimuli and lack distinct receptive fields, but it is unlikely that these are related to an afferent “pain” pathway.
Degeneration in the dorsal lateral geniculate nucleus of the rat following interruption of the retinal or cortical connections
Authors: Montero V. M. , Guillery R. W. 
Published: January 2005

AbstractTwo distinct fiber systems are recognizable in the dorsal lateral geniculate nucleus of the rat. One consists of small bundles running in a transverse plane from the ventrolateral to the dorsomedial parts of the nucleus, and the other is made up of longitudinal fibers which pass approximately antero‐posteriorly through the nucleus parallel to the columns of cells that represent restricted retinal areas (Montero et al., '68).The Nauta method, used after suitable lesions, shows that the transverse bundles carry corticofugal and retinogugal fibers. The former lie mainly in the ventromedial parts of the nucleus and the latter in the dorsolateral parts, but the two groups are also mingled within individual transverse bundles. Both groups send fibers into the lateral geniculate nucleus and each also continues beyond the nucleus. The fibers that ramify in the nucleus leave the transverse bundles and run in the longitudinal system as they break up into a pericelluar plexus. There is evidence that both groups have a terminal distribution along the lines of projection of retinal points.Four days after a lesion within visual area I the degenerating corticogeniculate fibers form a fine plexus limited to the anterior half of the segment that would show retrograde cell degeneration with longer survival times. Seven and 13 days following a cortical lesion the retrograde cell changes obscure the fine corticogeniculate degeneration, but coarse geniculocortical fibers that are undergoing indirect Wallerian degeneration can be seen in the longitudinal system.