bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fiber projections from trigeminal nucleus caudalis in primate (squirrel monkey and baboon)
Authors: Tiwari Rajendra K. , King Robert B. 
Published: January 2005

AbstractSmall radiofrequency lesions were produced in the trigeminal nucleus caudalis and adjacent lateral reticular formation (LRF) in seven squirrel monkeys and four baboons. Frozen brain sections were stained for cellular morphology and for axonal and terminal degeneration. The lesions in pars marginalis and gelatinosa produced terminal degeneration in pars magnocellularis and LRF. Pars magnocellularis lesions produced degeneration into the ascending trigeminal intranuclear tract and the adjacent lateral reticular formation. Ascending thalamic and reticular projections emanated from LRF lesions. These observations suggest that elements of the LRF adjacent to the nucleus caudalis are an integral part of the trigeminal somesthetic fiber projection system and may subserve the perception of noxious stimuli.
Cycle times of the neural epithelial cells of various types of neuron in the rat. An autoradiographic study
Authors: Schultze Brigitte , Nowak Bogdan , Maurer Werner 
Published: January 2005

AbstractCell kinetic studies of the proliferation of the neural epithelium during the embryonic development of the rat brain are described.Pregnant rats received a single injection of 3H‐thymidine (3H‐TdR) between the tenth and twenty‐first day of pregnancy. Autoradiographs of the brains of the 25‐day‐old offspring were prepared. For a number of different cell types (table 1, II) the percentage of labeled neurons as a function of time of prenatal 3H‐TdR injection was determined.The end of the proliferating period of the neural epithelial cells of certain cell types can be derived from these percentages of labeled cells (table 1, V). Further‐more, it can be demonstrated that the percentage of labeled neurons is equal to the labeling index of the neural epithelial cells of these cell types at the time of prenatal 3H‐TdR injection.Based on the labeling index of the neural epithelial cells and their S phase, cycle times can be calculated. This way it is possible for the first time to determine the cycle times of those neural epithelial cells that later on differentiate into a certain type of neuron (table 1, IV).The calculated cycle times show that up to the sixteenth prenatal day the neural epithelial cells behave like a homogeneous cell population which proliferates with an approximately constant cycle time of about half a day. The cycle time seems to increase with increasing fetal age.From the total number of a certain type of neuron the number of mitotic divisions or cycle times respectively can be derived which is necessary to produce the number of neural epithelial cells providing these neurons. With regard to the mean cycle time of the neural epithelial cells it can be concluded that the beginning of proliferation of the neural epithelial cells coincides with the formation of the neural plate on the ninth day of embryonic development or starts even shortly before this time.
Retinogeniculate projections in the rabbits of the albino allelomorphic series
Authors: Sanderson K. J. 
Published: January 2005

AbstractRetinogeniculate pathways have been studied by fiber degeneration and autoradiographic methods in rabbits that are homozygous for alleles of the albino series of genes. It has been found that albino and Himalayan rabbits, which both lack all melanin pigment in the eye, have a similar abnormality of the retinogeniculate pathway. The number of ipsilateral optic fibers going to the lateral geniculate nucleus is reduced in these rabbits, the ipsilateral projection forms a discontinuous terminal zone instead of the normal continuous zone, and some of the ipsilateral axons terminate in an inappropriate part of the nucleus, so that regions receiving a crossed input in normal rabbits receive an uncrossed input in the abnormal rabbits. Chinchilla rabbits show a slightly reduced fur pigmentation but have a normal distribution of pigment in the retinal pigment epithelium and these rabbits have normal retinogeniculate pathways.In addition, the normal retinogeniculate pathway was studied. Autoradiographic methods show that the β segment of the lateral geniculate nucleus receives a contralateral input. Hence, earlier views that this segment projects to the visual cortex but receives no retinal input, are untenable. Further, in the autoradiographic material it was not possible to identify separate ipsilateral laminae and it was concluded that in the normally pigmented rabbit the ipsilateral retinogeniculate projection forms one relatively continuous group.
The distribution of acetylcholinesterase in buds of the rat vallate papilla as determined by electron microscope histochemistry
Authors: Paran Nava , Mattern Carl F. T. 
Published: January 2005

AbstractThe distribution of acetylcholinesterase (AChE) in the rat vallate papillary bud was investigated by histochemical electron microscopy. Previous reports of specific AChE activity around subgemmal and intragemmal nerves and between some taste bud cells have been confirmed. In addition we have consistently observed dense precipitation between microvilli in the taste pore. The studies suggest that the neurotransmitter, acetylcholine, may be involved in early events in the taste process which are believed to occur in the pore.
The radial fibers in the globus pallidus
Authors: Fox C. A. , Rafols J. A. 
Published: January 2005

AbstractIn our Golgi collection of adult monkey brains the striatal efferents, i.e., the radial fibers in the globus pallidus and the “comb” bundle fibers in the internal capsule and in the cerebral peduncle, are well impregnated in the horizontally sectioned brain and in a sagittal sectioned brain. Since collaterals emerging from radial fibers are seen only in the horizontal series and not in the sagittal series, the interpretation is that they proceed anteriorly and posteriorly only, following the curvature of the pallidal segments, and do not run superiorly or inferiorly as they emerge.Although radial fibers emitting collaterals in the lateral segment and in the medial segment of the globus pallidus have been observed, it has not been possible to observe the same radial fiber emitting collaterals in both pallidal segments and the prospects of ever doing so are not good. The radial fibers converging in the globus pallidus pursue many radii and there is little coincidence between the plane of section and the planes in which they travel. At most only severed radial fiber segments 100–150 microns in length can be found in the horizontal sections needed to observe the collaterals. Moreover, sagittal sections show that radial fibers are deflected in their course, either dorsoventrally or ventrodorsally, as they pass through the internal medullary lamina to enter the medial segment of the globus pallidus.The radial fibers in the medial segment of the globus pallidus are continuous with the “comb” bundle fibers and appear to be thinner than the radial fibers in the lateral segment of the globus pallidus. It is not proved; nonetheless, the view expressed here is that the radial fibers are thinner in the medial segment of the globus pallidus because they may be the same fibers that gave off collaterals in the lateral segment of the globus pallidus. This is discussed in the light of the electrophysiological disclosure of Yoshida et al. ('71, '72) that caudatopallidal fibers are collaterals off caudatonigral fibers.The afferent plexuses of fine, “bouton en passage” fibers, which completely ensheath the long radiating dendrites in the globus pallidus (Fox et al., '66) are well impregnated in the horizontal series. Obviously, they are formed by a number of ultimate branches converging from the collateral branches of a number of different radial fibers. The divergence, too, in this system must be considerable; however, its true extent can only be surmised from the severed radial fibers and radial fiber collaterals seen in the incompletely impregnated Golgi section. One severed segment of a radial fiber displays three collaterals and one of these collaterals has five branches, one of which can be traced to a point where it gives off an ultimate branch in an afferent, dendrite‐ensheathing plexus.
Computer measurements of axis cylinder diameters of radial fibers and “comb” bundle fibers
Authors: Fox C. A. , Rafols J. A. , Cowan W. M. 
Published: January 2005

AbstractIn electron micrographs of the squirrel monkey (Saimiri sciureus) brain the striatal efferents were observed at two different levels in their course: (1) in cross‐sectioned radial fiber bundles just before they enter the globus pallidus; (2) in cross‐sectioned “comb” bundle fibers just before they enter the substantia nigra. In the radial bundles nearly all of the fibers are myelinated; in the “comb” bundle most are unmyelinated. The polarity of all the “comb” bundle fibers is descending. None of them degenerate following a large lesion in the substantia nigra but they do degenerate following a large lesion in the striatum. Also following this latter lesion the endings with large synaptic vesicles, which make up most of the endings in the globus pallidus and the substantia nigra, degenerate.For computer measurements, electron micrographs of the radial bundle were enlarged photographically to a final magnification of 20,000; those of the “comb” bundle to × 50,000. Measurements of 1309 radial fibers revealed a mean axis‐cylinder diameter of 0.68 microns, and measurements of 749 unmyelinated “comb” bundle fibers gave a mean axis‐cylinder diameter of 0.21 microns. Myelinated fibers were not included in the “comb” bundle measurements because it contains myelinated fibers of pallidal origin in addition to myelinated fibers of striatal origin.The results here indicate that the striatal efferents undergo a decided decrease in axis‐cylinder diameter during their transit through the globus pallidus. It is suggested that the large non‐spine bearing neurons in the striatum are the source of the striatal efferents and that they send their axons into the substantia nigra and enroute spend a great quantity of their axoplasm by extending extensive collaterals in both segments of the globus pallidus. This could account for the decreased caliber of the striatal efferents in the “comb” bundle and other findings in the striatum, globus pallidus and substantia nigra.
Demonstration of terminalis, olfactory, trigeminal and perivascular nerves in the rat nasal septum
Authors: Bojsen‐Møller Finn 
Published: January 2005

AbstractThe innervation of the nasal septum and around the olfactory bulb has been investigated in rats by means of whole‐mount preparations and histological sections. Silver staining, OsO4 staining, PAS staining, cholinesterase reaction and fluorescence for catecholamine‐containing nerves were used. The nervus terminalis forms on the medial side of the olfactory bulb a ganglionated plexus, from which branches are given off which course peripherally with the vomeronasal nerves. From a dorsal part of the terminalis nerve plexus an anterior branch is given off which runs along the anterior ethmoidal nerve to the nasal vestibule where it connects with a group of ganglia. The peripheral branches of the nerve run from here along two epithelial cristae formed histologically like dermal papillae. Ventrally in the respiratory region at the junction of the nasal cavity and the nasopharynx is a 1 × 2 mm area with olfactory epithelium, glands of Bowman and an independent innervation from the olfactory bulb. This is the so‐called septal olfactory organ. Trigeminal nerves form a plexus in the respiratory region and in the vestibule, but do not supply the olfactory region. Catecholamine‐containing and cholinesterase‐positive nerves run along the meningeal arteries on the cribriform plate and accompany their branches to the vascular plexus in the olfactory and respiratory regions. Double innervation is found not only of this vascular plexus but of the venous sinuses in the swell bodies of the vestibule. The glands of the nose are not surrounded by catecholamine‐containing nerves.
A scanning electron microscopic study of the morphology and geometry of neural surfaces and structures associated with the vestibular apparatus of the pigeon
Authors: Landolt Jack P. , Correia Manning J. , Young Eric R. , Cardin Ronald P. S. , Sweet Robert C. 
Published: January 2005

AbstractThe scanning electron microscope (SEM) was used to investigate the morphology of the neuroepithelial regions of the vestibular ampullary structures in 47 White King pigeons. The specific neural surfaces studied were (1) the cristae ampullares of the vertical and lateral membranous ampullae, (2) the hair cells lining the cristae, (3) the ampullary nerve fibers, and (4) the bipolar cells of the vestibular (Scarpa's) ganglion. Additionally, some observations of the gross anatomical structures of the bony labyrinth are given. Arguments are advanced which show that if the surface area of a given semicircular canal can be projected onto one of the three normal head planes, then that canal can be made to respond to motion in the appropriate plane, provided that the projected area is sufficiently large to achieve a threshold pressure as determined by a generalized form of Groen's equation ('57). With regard to the cristae ampullares, it is hypothesized that their surface areas can be described by means of a revolved catenary, i.e., a catenoid of revolution. (The catenary is found in nature as the approximate shape taken by a flexible cable when it is suspended at two points). The surface area of a catenoid provides a minimum surface of revolution. In the context of a crista, this implies that the given number of hair cells could not be fitted onto a smaller surface area. One advantage of this is that nature is able to utilize a thinner cupula than would be possible with other configurations and therefore an increased sensitivity to cupular motion can be realized. A second important factor is that all hair cells must revolve (by way of cupular motion) about the same centre of rotation in response to angular acceleration. Thus, all of the orthogonally‐positioned hair cell tufts on the cristae surface may be stimulated simultaneously by way of a tangential shear. Other arguments show that the classical “swinging door” type of cupular motion is not consistent with SEM and other recent observations. Two alternate modes of cupular motion are presented, each of which requires far less energy expenditure than does the “swinging door” cupula. The suggestion is then made that, during normal head movements, the cupula behaves as a drum much like the tympanic membrane and that only for large, non‐physiological motions does the “swinging door” mode of cupular motion take place. It must be remembered, however, that cupular motions during normal physiological head movements are infinitesimally small (Oman and Young, '72).
The distribution of the alpha type of ganglion cells in the cat's retina
Authors: Wässle H. , Levick W. R. , Cleland B. G. 
Published: January 2005

AbstractThere is a distince class of large ganglion cell bodies observable in whole‐mount preparations of the cat's retina stained with cresyl violet. Measurements of perikaryal size and its variation with eccentricity from the central area support the indetification of the large cells with the class of alpha cells previously defined in Golgi‐stained preparations. A complete enumeration of alpha cell sin one retina yielded a total of 6212. They were encountered in all parts of the retina and had a peak density within the central area (200/mm2). The retinal distribution was displayed as a contour map of alpha‐cell density. Away from the central area, the lines of iso‐density had the form of a 4‐pointed star with rather blunt points corresponding to horizontal and vertical ridges of augmented density. Along horizontal, vertical and oblique strips through the central area, alpha‐cell density was an approximately constant fraction of total ganglion cell‐density. The averag; value of the fraction was 3.3% from which it has been calculated that the cat's retina may contain as many as 190,000 ganglion cells.
Color‐specific interconnections of cones and horizontal cells in the retina of the goldfish
Authors: Stell William K. , Lightfoot David O. 
Published: January 2005

AbstractIn Golgi preparations of goldfish retina we have observed three types of horizontal cell which receive exclusively from cones and one which receives exclusively from rods. The cone horizontal cells were designated H1, H2 and H3, in order of increasing dendritic spread, increasing separation from the outer synaptic layer, decreasing size of perikaryon, and decreasing density of cone contacts. Slender appendages with knobby terminal enlargements project horizontally from the perikarya and larger dendrites of both rod and cone horizontal cells.We determined patterns of cone inputs to Golgi‐impregnated horizontal cells by analyzing serial 1 μm sections with the light microscope. The probable inputs, in terms of visual pigments in the cones which contact them, are: H1, red + green + blue; H2, green + blue; H3, blue. Analysis of previously published work suggests (1) that H1 cells generate monophasic or L‐type responses, H2 cells generate biphasic or C1‐type responses, and H3 cells generate triphasic or C2‐type responses; (2) that H1 cells receive direct functional input at least from red‐sensitive cones, H2 cells from green‐sensitive cones, and H3 cells from blue‐sensitive cones; and (3) that H1 cells constitute pathways from cones to H2 cells, and H2 cells constitute pathways from cones and H1 cells to H3 cells. The precise location and route of the transfers, from H1 to H2 and from H2 to H3, are not yet known.
Involvement of the avian amygdalar homologue (archistriatum posterior and mediale) in defensively conditioned heart rate change
Authors: Cohen David H. 
Published: January 2005

AbstractArchistriatal involvement in visually conditioned heart rate change (established by pairing light and foot‐shock) was studied in 198 pigeons by evaluating conditioning performance following lesions of different archistriatal subdivisions or interruption of their subtelencephalic projections. Lesions of the anterior‐intermedium archistriatum or interruption of its descending projection (tractus occipitomesencephalicus) had no effect on conditioned response development. In contrast, destruction of the posterior‐mediale region or interruption of its descending projection (tractus occipitomesencephalicus, pars hypothalami) produced profound conditioning deficits. The findings are entirely consistent with a recent anatomical analysis (Zeier and Karten, 1971) suggesting that only the posterior‐mediale archistriatum constitutes the avian amygdalar homologue. It is concluded that the integrity of the posterior‐mediale region and its projection to the hypothalamus via the tractus occipitomesencephalicus, pars hypothalami are essential for establishing visually conditioned heart rate change in a defensive conditioning paradigm, and these findings are discussed in the context of structures previously implicated in mediating this conditioned autonomic response.
The number, size and spatial distribution of neurons in Lamina IV of the mouse SmI neocortex
Authors: Pasternak Joseph F. , Woolsey Thomas A. 
Published: January 2005

AbstractWe located the corresponding barrel in Layer IV of the mouse Sml cortex in eleven cerebral hemispheres sectioned in a plane tangential to the pia overlying Sml and in one sectioned in a plane normal to the pia. All of the brains were serially sectioned and prepared by a combined Golgi‐Nissl method. In the section in which barrel C‐1 could be optimally visualized each neuronal soma was outlined with a camera lucida and the cross‐sectional area measured with the aid of a small computer.In all, nearly 7,000 neurons were measured. We estimate that on average barrel C‐1 contains about 2,000 neurons. The mean cross‐sectional area of the perikarya is 62.51 μ2 (S.D. ± 14.51 μ2) and the size distribution of the neurons is unimodal and positively skewed. There is no segregation of cells within the barrel on the basis of size. The spatial distribution of cells in the barrel is fairly constant, from specimen to specimen, and the characteristic cytoarchitectonic appearance of the barrel can be related to regional neuronal packing density sicne there are at least 1.6 as many neurons in the sides of the barrel as the hollow.The constancy of the cellular composition of the barrels indicates that the mechanisms responsible for the development of the mouse SmI cortex are fairly rigidly determined, and that the barrel field should lend itself well to further quantitative, developmental and physiological analysis.
The ascending projections of the superior colliculus in the rhesus monkey (Macaca mulatta)
Authors: Benevento L. A. , Fallon James H. 
Published: January 2005

AbstractWe studied and compared the ipsilateral afferents of the superficial and deep layers of the superior colliculus of the rhesus monkey. Using a stereptaxic method, microelectrodes were inserted through the contralateral hemisphere in order to make electrolytic lesions of the superior colliculus. Large lesions involved all layers of the superior colliculus, while smaler lesions involved either the superficial or the deep layers of the superior colliculus. Following various survival times, the brains were prepared with the Fink‐Heimer technique (1967). Following lesions of the superficial layers of the superior colliculus, definite degenerated axonal endings were found in the dorsal and ventral lateral genuculate nuclei, inferior pulvinar, centrontermediate nucleus, magnocellular dorsomedial nucleus, anterior pretectal nucleus and pretectal refion. Sparse degenerated axonal endings were found in the limitans nucleus, lateral posterior nucleus and some intralaminar nuclei following lesions of the superficial layers in the rostral portion of the superior colliculus. Following lesions of the deep layers of the superior colliculus, degenerated axonal endings were found in the central gray, magnocellular medial geniculate nucleus, suprageniculatre nucleus, limations nucleus, lateral posterior nulceus, medial and oral pulvinarm nucleus of athe accessory optic tract, zona incerta, subdivisions of the ventral lateral and ventral posterior lateral nuclei, ventral posterior inferior nulceus, densocellular and mulriform dorsomedial nuclei, all intralaminar nucleim inferior coliculus, parabigeminal nucleus, olivary nucleus, reunions nucleus, Forel's Field H and an undefined midbrain nucleus. In general the projections were topographically organized in that the caudal portions of thalamic nuclei. All the degeneration patterns seen after lesions of the superficial and dep layers were accoundted for by large lesions which involved all layers of the superior colliculus. It is conclude that the superficial and deep layers of the rhesus monkey superior colliculus have different ascending projections. The findings are related to the organization of visual and multimodal thalamocortical system in primates and other mammals.