bluuebunny/crossref_metadata_2025 huggingface dataset:
The origin, course and termination of corticospinal fibers in the slow loris, Nycticebus coucang (boddaert)
Authors: Campbell C. Boyd G. , Yashon David , Jane John A.
Published: January 2005

The origin and distribution of corticospinal fibers in the slow loris (Nycticebus coucang) were studied with the aid of the Nauta‐Gygax technique following selected ablations of portions of the left cerebral cortex. Reconstruction of the cortical area which contributes to the corticospinal tract reveals a “motor” area which approximates that of Perodicticus, another lorisiform lemur, mapped by electrophysiological methods. Degenerated corticospinal fibers found in the contralateral lateral funiculus were traced caudally to sacral segments. A small number of degenerated fibers were also found in the ipsilateral lateral funiculus as far caudally as the lumbar cord. Preterminal fiber degeneration was most abundant in the contralateral dorsal horn and zona intermedia. Similar, but less abundant, degeneration was found in the contralateral ventral horn. Some degenerating fibers re‐crossed through the dorsal and ventral gray commissures to the ipsilateral gray matter where preterminal fiber degeneration was most abundant in the medial portions of the ventral horn. Degenerating corticospinal fibers could be seen among the large, laterally‐placed cells of the contralateral ventral horn.
Efferent connections of the olfactory bulb in the cat. An experimental study with silver impregnation methods
Authors: Mascitti Tomás Andrés , Ortega Susana N.
Published: January 2005

After lesions of the olfactory bulb with some involvement of the anterior olfactory nucleus in the cat the ensuing degeneration was studied with both the Nauta and the Glees silver impregnation techniques. Preterminal and terminal degeneration was found in the anterior olfactory nucleus, pars lateralis and pars externa; the rostrolateral part of the olfactory tubercle; prepyriform and periamygdaloid cortices; anterior amygdaloid area; nucleus of the lateral olfactory tract and nucleus corticalis of amygdala, homolaterally. On the contralateral side the degeneration was restricted to the pars externa of the anterior olfactory nucleus and to the granular layer and the inner part of the internal plexiform layer of the olfactory bulb.

In the olfactory tubercle and pyriform cortex the degeneration was located in the plexiform layer in which there were seen degenerating axo‐dendritic synaptic contacts on the ascending dendrites of the pyramidal cells.

The olfactory projection fibers which reach the contralateral anterior olfactory nucleus and bulb course through the anterior limb of the anterior commissure. In the olfactory bulb the fibers were found to end not only among the neuropil of the internal pleximorm and granular layers but also as axo‐somatic contacts on the granular cells. The mitral cells and the periglomerular layer were completely free from degeneration.

No degeneration was observed homolaterally in the rest of the amygdaloid complex, septal areas, bed nucleus of the anterior commissure, interstitial nucleus of the stria terminalis or hippocampus.
Ponto‐sacral connections in the medial reticulo‐spinal tract subserving storage of urine
Authors: Kuru Masaru , Iwanaga Takesi
Published: January 2005

At high intravesical pressure, electrical stimulation of the ventrolateral reticular formation of the rostral pons provokes relaxation of the urinary bladder in cats (Iwanaga, '61). After confirming the vesico‐relaxer response a minute lesion was made electrically corresponding to the tip of the electrode and the descending degenerations were traced by the Marchi technique. From this region originate a special group of ponto‐sacral connections, which, participating in the medial reticulo‐spinal tract, terminates in the ventral horn cells of the lumbo‐sacral division of tie cord. Lesion on one side causes bilaterally descending degeneration, the contralaterally descending component being predominant. These ponto‐sacral connections have collaterals to the homolateral pontine detrusor nucleus (Kuru and Yamamoto, '64), to the contralateral ventrolateral reticular formation of the rostral pons and to the bulbar vesico‐relaxer center (Kuru et al., '60), Since electrical stimulation of this pontine region results in an augmentation of discharge in the external urethral sphincter (Kuru et al., '63) in addition to vesical relaxation at high intravesical pressure, this kind of ponto‐sacral connections is concluded to subserve storage of urine.
An experimental study of the spino‐olivary fibers in the rabbit and the cat
Authors: Mizuno Noboru
Published: January 2005

The spinal afferents to the inferior olive were investigated in 15 rabbits and 17 cats, in which lesions of various extent were made at various levels of the spinal cord and the ensuing degeneration of the spino‐olivary fibers was studied by the Marchi and Nauta methods.

The organization of the spino‐olivary system of the rabbit is essentially similar to that of the cat, except for some details concerning the lateral cervical nucleus.

The spino‐olivary fibers take origin chiefly in the posterior horn and possibly also in the intermediate zone at practically all levels of the spinal cord and ascend bilaterally through the anterior and the adjacent part of the anterolateral funiculus in close topographical relationship with the spinoreticular fibers and Gowers' fasciculus to terminate in the medial and the dorsal accessory olives. The termination in the olive is bilateral, but more marked contralateral to the nuclei of origin. The fibers from the lumbosacral cord are more numerous than those from cervicothoracic cord. While the majority of the fibers are considered to be collaterals chiefly of the spinoreticular and partly of the spinothalamic fibers, a considerable amount of true spino‐olivary fibers appears to terminate in the caudal region of the medial and the dorsal accessory olives.

The lateral cervical nucleus cannot be considered the main source of the spino‐olivary fibers.

Some details concerning the terminal distribution of the spino‐olivary fibers are discussed.
Morphological changes occurring in the developing chick choroid plexus
Authors: Smith Diane Elizabeth
Published: January 2005

The present study was undertaken to observe the morphological changes which take place during the histogenetic development of the chick telencephalic choroid plexus between the eighth and twentieth day of embryonic life. The plexuses were removed under the dissecting microscope and processed by freezedrying. The paraffin‐embedded sections were stained according to Cowdry's method for mitochondria and with Periodic Acid Schiff's reagent for glycorgen. The sections were viewed using bright light and phase optics.

The most pertinent findings involved (1) a change in the epithelium from a pseudostratified to a low columnar cell type and (2) an increase in the number of mitochondria with their final distribution pattern being at the brush border of the choroidal epithelium. These changes developed between the ninth and twelfth day and became stabilized by the sixteenth day. The significance of the morphological changes and the possible correlation between the mitochondrial location and number and some physiological features of active transport is discussed.
Myeloarchitectonics of the occipital cortex in dog and general remarks on the myeloarchitectonics of the dog
Authors: Kreiner Jerzy
Published: January 2005

The paper presents an analysis of the occiptal lobe of the dog from the point of view of myeolarchitectonics based on the author's own scheme. Thirty‐three areas have been distinguished in the region studied. The principles of the new scheme for the description of the myeloarchitectonics and the new notion of the myeloarchitectonic area and its division into sub‐areas are offered and discussed. The correlation of different myeloarchitectonic elements within an area is stressed. Three types of areas are distinguished in the cortex, namely, gyral, fissural and paragyral areas; attention is given to their occurrence not only in gyri and fissures but in regions of unfolded cortex, also whereby they form crypto‐gyri and crypto‐sulci. On the basis of this division some suppositions are made as to the mechanism of formation of gyri and sulci.
Changes of photically‐evoked potentials in lateral geniculate body during retrograde degeneration
Authors: Dewson James H. , Chow Kao Liang
Published: January 2005

Potentials evoked both by light flash and by electrical shocks to the optic chiasma and optic tract were recorded from the lateral geniculate body during retrograde degeneration. Six rabbits and six cats were studied for up to 22 weeks following ablation of primary visual cortex. Results indicate that amplitude changes over time show the same general trends for both species, although specific differences were noted. Interpretation of the electrophysiological data is made with regard to the histological findings reported in the preceding study.
A quantitative study on the postnatal development of the cerebellar vermis of mouse
Authors: Haddara M. A. , Nooreddin M. A.
Published: January 2005

The postnatal changes in the cross‐sectional area of the cortex and white matter in the median sagittal section of the cerebellum of mouse were studied quantitatively. That of the cortex increases about 20 fold from birth to maturity, increasing slowly during the first five days following birth, then sharply during the next five days to resume slow increase again after the tenth day. There is very little increase after the fifteenth day. That of the white matter increases only four‐fold during the same period. By the end of the second week it has attained only half of its adult value and continues to increase even after the thirtieth day.

The increase in the cross‐sectional area of the cerebellar cortex is mainly due to rapid expansion of the cortical surface which forces the white matter to be arranged into medullary rays (actually ridges) to keep in contact with the rapidly expanding cortex, thus cerebellar fissures are formed.

The number of mitotic figures (uncorrected for fragments) in the superficial granular layer in a median sagittal section 10 m̈ thick increases from about 22 at birth to a peak of 230 at seven days then falls to less than 36 at 15 days of age, after which the entire layer disappears.
Neurofibrillar differentiation during embryonary growth
Authors: Vazquez‐Nin G. H. , Sotelo J. R.
Published: January 2005

The spinal cord and the acoustic primordium of the chick embryo (3 to 7‐day‐old) were investigated by electron microscopy. Special attention was devoted to the structure of neurofilaments and tubules in the neuroblasts and cells of the crista acustica.

The neurofilaments were observed to be related at early stages of development to the RNA particles of the cytoplasm (Palade's particles). This relationship is observed in particular fields which are clearly distinguished because they show fewer particles than the surrounding cytoplasm. The first stage is characterized by the presence in these fields of short branched filaments, which frequently are in contact with the ribosomes. The filaments grow in length and become ordered during a later period. At the same time, the fields become free of the basophilic particles.

Tubules about 300 Å thick were found in neuroblasts and their prolongations (central nervous system); in the acoustic nerve, fibers of the “tubule type” or of the “neurofilament type” are described. Filaments and tubules showing similar morphology were also observed in the acoustic epithelium (crista acustica). The filaments seem to originate in the same way as in the neuroblasts. A close relationship between tubules and centrioles was found. The origin of the neurofilaments is discussed in relation to the filaments of proteinic nature described in other cell types.
Monoamine‐containing neurons in the nerve cord and body wall of Lumbricus terrestris
Authors: Rude Sonia
Published: January 2005

This study represents an attempt to reconcile recent quantitative findings of large amounts of monoamines in the earthworm with early histological findings of only small numbers of chromaffin cells in that animal. Using the highly sensitive and specific fluorescence method for the histochemical localization of monoamines, it has been demonstrated that the earthworm nervous system contains large numbers of monoaminergic neurons. At least one‐tenth of the motor and interneuronal population in a typical ganglion of the ventral nerve cord contain either serotonin or primary catecholamines. In addition a large number of neurons containing a primary catecholamine form an extensive sensory system with their cell bodies in the epidermis and their axons terminating in the ventral nerve cord.
The diencephalon of the opossum in stereotaxic coordinates. I. The epithalamus and dorsal thalamus
Authors: Oswaldo‐Cruz E. , Rocha‐Miranda C. E.
Published: January 2005

This investigation consists on the identification of diencephalic cellular groups in the opossum and their fit to a standard brain. A statistical survey of the stereotaxic coordinates of neuroanatomical landmarks (commissura anterior, commissura posterior, nucl. habenulae medialis, sulcus striopallialis and the pedamentum) from coronal sections of brains of 19 South American (D. aurita) and four North American opossums (D. virginiana) was first performed. Speical precautions were taken to obtain sections at planes parallel to those of the stereotaxic instrument, or to ensure that any deviation thereof was accounted for in the measurements. The reconstruction of the standard brain is based on average coordinates from landmarks of the South American species. Estimates of the S. D. of each set of coordinates give a scatter no larger than 0.8 mm and as small as 0.1 mm from the average.

Identification and outlining of nuclei and main fiber tracts was achieved from the study of three series of the aurita species cut in coronal sections and one in horizontal, adjusted to the coordinates of the standard brain. Inter‐ and intraspecies adjustments are made possible by correlating certain reference points with craniometric or body weight measurements.

Thirteen representative figures provide the core of this work, together with a brief description of cellular groups pertaining to the epithalamus and dorsal thalamus. Data on the ventral thalamus and hypothalamus is given in a second paper (Oswaldo‐Cruz and Rocha‐Miranda, '67).
The diencephalon of the opossum in stereotaxic coordinates. II. The ventral thalamus and hypothalamus
Authors: Oswaldo‐Cruz E. , Rocha‐Miranda C. E.
Published: January 2005

This is a second paper on the diencephalon of the opossum (see Oswaldo‐Cruz and Rocha‐Miranda, '67), providing information on cell type and nuclear configuration of the ventral thalamus and hypothalamus (including area preoptica). Stereotaxic coordinates, resulting from a statistical survey, are given.
Observation on the supra‐optic decussations, in the albino rat
Authors: Minderhoud J. M.
Published: January 2005

Using the experimental method of fiber degeneration the fibers crossing the midline in the supra‐optic decussations were differentiated. The fibers of the supra‐optic decussations proved to be decussating fibers arising in the reticular formation of the pons and the midbrain and commissural fibers of the superior colliculus and of the globus pallidus. The longest fibers arise in the spinal cord. A topographical arrangement of all fibers, according to their place of origin or according to the place where they join the tract was found. The function of the majority of the supra‐optic fibers could be described in terms of the reticular formation of the cranial part of the brainstem.
Cytoplasmic basophilia in the nerve cells of the cerebral cortex. VI. The human temporal cortex
Authors: Pakkenberg Henning
Published: January 2005

An 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

The 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

Nerve 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

The 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

Projections 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

Degeneration 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

The 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

Serial 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

The 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

The 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

Attempts 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

The 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

The 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

The 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

All 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

The 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

The 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

A 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

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

The 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

The 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

The 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

The 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

A 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

The 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

Kangaroo 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.