bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quantitative studies of retinal ganglion cells in a turtle, Pseudemys scripta elegans. I. Number and distribution of ganglion cells
Authors: Peterson Ellengene H. , Ulinski P. S. 
Published: January 2005

AbstractMultiple pathways for the transmission of visual information from retina to brain have been described in reptiles, but little is known about their functional organization. These parallel channels begin at the retina, and we have therefore begun to study the functional organization of retinal ganglion cells in the turtle, Pseudemys scripta elegans. This paper describes the numbers and distribution of cells in the ganglion cell layer.To develop criteria for the identification of ganglion cells, we labelled them retrogradely by applying horseradish peroxidase (HRP) to the optic nerve. Ganglion cells were found to vary substantially in size and cytology. In low density areas of the retina, ganglion cells typically have cytoplasm with well developed Nissl substance, a distinct, pale nucleus, and a large nucleolus. In high density areas of retina, ganglion cells are small, densely staining, and gliaform. The average minimum proportion of ganglion cells in the ganglion cell layer is 75–80% of total profiles. No more than five or six percent of profiles in the ganglion cell layer are neurons which do not send an axon into the optic nerve (displaced amacrine cells or intraretinal association cells).The ganglion cell layer of P. s. elegans can be divided into a number of regions on the basis of cell density. Isodensity maps constructed from Nisslstained, wholemounted retinas indicate that there is an elongated region of high ganglion cell density, the visual streak, which extends from nasal to temporal retina and is oriented such that its long axis follows the horizontal axis of the eye. The streak is aligned with the externally visible iris line. Seen in cross‐section, the ganglion cell layer in the streak is three to four cells thick; in nonstreak retina, ganglion cells form only a monolayer of somas. Ganglion cell density drops off more rapidly above the streak than below it. The temporal arm of the streak is both shorter and broader than the nasal arm. There is a peak in ganglion cell density at the midpoint of the streak, in the approximate center of the retina. Here, ganglion cell densities exceed 20,000 cells mm−2. The total number of ganglion cells in the retina is 350,000–390,000.
Layer I of striate cortex of Tupaia glis and Galago senegalensis: Projections from thalamus and claustrum revealed by retrograde transport of horseradish peroxidase
Authors: Carey Russell G. , Fitzpatrick David , Diamond Irving T. 
Published: January 2005

AbstractWe have examined the origin of the subcortical projections to the superficial layers of the striate cortex in Tupaia glis and Galago senegalensis by using the retrograde transport of HRP. Crystals of HRP were laid directly on the moist pial surface of the cortex which had been gently pricked with a small glass pipette. The diffusion of HRP was limited to layers I and II by restricting the length of time that the HRP was in contact with the surface. Following the application of HRP to the striate cortex, labeled cells were found in restricted regions of the lateral geniculate body of both species. Layers 4 and 5 of galago and layer 3 of tree shrew contained dense clusters of labeled cells. Labeled neurons were also found in the zones between the layers of the lateral geniculate body in species and these cells were always in register with the labeled cells within the layers. In galago, curved columns of labeled cells were observed in the inferior and superior subdivisions of the pulvinar nucleus. These columns were arranged in the shape of two arcs, joined at the fiber bundle which separates the two subdivisions. The position of the bands in the pulvinar nucleus varied with the locus of the application in the striate cortex. While no labeled cells were seen in the body of the pulvinar nucleus of tree shrew, small labeled neurons were found in the external medullary lamina forming the capsule of the pulvinar nucleus. These cells were continuous with a larger population of labeled cells in the lateral intermediate nucleus. In both species, labeled cells were also found in the intralaminar nuclei (particularly the paracentral nucleus) and in the dorsal‐caudal portion of the claustrum. In the claustrum, few unlabeled neurons were present within the zone containing labeled cells. In conclusion, layer I of striate cortex appears to be the site of convergence of several projection systems originating from principal and intralaminar thalamic nuclei as well as the claustrum. The significance of this overlap is discussed in terms of the total cortical extent of each system.
The connections of the septal region in the rat
Authors: Swanson L. W. , Cowan W. M. 
Published: January 2005

AbstractThe efferent, afferent and intrinsic connections of the septal region have been analyzed in the rat with the autoradiographic method. The lateral septal nucleus, which can be divided into dorsal, intermediate and ventral parts, receives its major input from the hippocampal formation and projects to the medial septal‐diagonal band complex. The ventral part of the nucleus also sends fibers through the medial forebrain bundle to the medial preoptic and anterior hypothalamic areas, to the lateral hypothalamic area and the dorsomedial nucleus, to the mammillary body (including the supramammillary region), and to the ventral tegmental area. The medial septal nucleus/diagonal band complex projects back to the hippocampal formation by way of the dorsal fornix, fimbria, and possibly the cingulum. Both nuclei also project through the medial forebrain bundle to the medial and lateral preoptic areas, to the lateral hypothalamic area, and to the mammillary complex. The medial septal nucleus also sends fibers to the midbrain (the ventral tegmental area and raphe nuclei) and to the parataenial nucleus of the thalamus, while the nucleus of the diagonal band has an additional projection to the anterior limbic area. Ascending inputs to the medial septal nucleus/diagonal band complex arise in several hypothalamic nuclei and in the brainstem aminergic cell groups. The posterior septal nuclei (the septofimbrail and triangular nuclei) receive their major input from the hippocampal formation, and project in a topographically ordered manner upon the habenular nuclei and the interpeduncular nuclear complex.The bed nucleus of the stria terminalis receives its major input from the amygdala (Krettek and Price, '78); but other afferents arise from the ventral subiculum, the ventromedial nucleus, and the brainstem aminergic cell groups. The principal output of the bed nucleus is through the medial forebrain bundle to the substantia innominata, the nucleus accumbens, most parts of the hypothalamus and the preoptic area, the central tegmental fields of the midbrain, the ventral tegmental area, the dorsal and median nuclei of the raphe, and the locus coeruleus. The bed nucleus also projects to the anterior nuclei of the thalamus, the parataenial and paraventricular nuclei, and the medial habenular nucleus, and through the stria terminalis to the medial and central nuclei of the amygdala, and to the amygdalo‐hippocampal transition area.
The raphe nuclei of the rabbit brain stem
Authors: Felten David L. , Cummings John P. 
Published: January 2005

AbstractThe raphe nuclei of the rabbit brain stem were found in the midline and adjacent reticular formation of the medulla, pons, and mesencephalon. Nuclei raphe obscurus, pallidus, and magnus were located in the medulla. Nucleus raphe pontis and the caudal portion of nuclei raphe dorsalis and centralis superior were present in the pons. The rostral portion of nuclei raphe dorsalis and centralis superior, and nuclei linearis caudalis and intermedius were present in the msencephalon. Wings of neurons extended from the midline clusters of raphe neurons into the adjacent reticular formation. These wings of neurons contained serotonergic perikarya which were cytoarchitecturally indistinguishable from the midline neurons. A detailed localization of these nuclei is presented in atlas form. These raphe nuclei contained hetrogeneous populations of neurons which varied in the size, shape and density of the cell bodies. In addition, the dendritic branching, specific orientation of dendrites, and appearance of spines were distinct for each of the raphe nuclei. Individual raphe nuclei often contained several subpopulations of neurons characterized by unique spatial configuration and orientation. The main morphological similarities of the raphe nuclei are location in or adjacent to the midline, the presence of serotonergic cell bodies in all raphe nuclei except the linear nuclei, and heterogeneous cell populations.
The longitudinal zonal pattern in the paramedian lobule of the cat's cerebellum: An analysis based on a correlation of recent HRP data with results of studies with other methods
Authors: Walberg F. , Brodal A. 
Published: January 2005

AbstractIn a preceding study of the distribution of retrogradely labeled cells in the inferior olive of the cat after microinjections of horseradish peroxidase (HRP) in the contralateral paramedian lobule (Brodal and Walberg, 1977b), three longitudinal zones were distinguished. The zones were assumed to correspond to Voogd's zones C1, C2 and D, receiving their afferents from parts of the dorsal accessory olive, of the medial accessory olive and of the dorsal lamella of the principal olive, respectively. Labeled cells were not found in the ventral lamella of the principal olive, however, although there is no doubt that also this projects to the paramedian lobule.In the present study, iontophoretic ejections, covering the extreme lateral part of the paramedian lobule, gave rise to labeling of cells in the ventral lamella. It is concluded that the zone D in the paramedian lobule can be subdivided into two, a lateral, D2 and a medial, D1, receiving fibers from the ventral and dorsal lamella, respectively. Neither zone extends throughout the entire length of the paramedian lobule. Both are lacking most rostrally and most caudally.This and other findings prompted a renewed analysis of the entire pattern of zonal representation in the paramedian lobule, based on correlations of our observations with the HRP method with data obtained with other methods. The results of this analysis are briefly described and summarized in a diagram (fig. 3B). It is particularly remarkable that zone B is present in some folia medially. A somatotopical arrangement appears to be present within all zones. A full account and documentation will be presented separately (Brodal and Kawamura, 1980).
The inferior pulvinar complex in owl monkeys: Architectonic subdivisions and patterns of input from the superior colliculus and subdivisions of visual cortex
Authors: Lin C.‐S. , Kaas J. H. 
Published: January 2005

AbstractPatterns of connections with other visual structures and architectonic characteristics were used to subdivide the inferior pulvinar complex of owl monkeys into three distinct nuclei termed the central inferior pulvinar, IPc, the medial inferior pulvinar, IPm, and the posterior inferior pulvinar, IPp. IPc occupies about 70%; IPm about 20%, and IPp about 10% of the inferior pulvinar complex. Encapsulating fiber bands distinguish the boundaries of the three nuceli. IPm is also identified by a much greater packing density of neurons than IPc and IPp. Both IPp and IPc receive input from the superior colliculus, but the terminations in IPp are denser. Visual cortical Areas 17, 18, MT, DM, M and PP (Allman and Kaas, '76) project to IPc and IPm in patterns that indicate that central vision is represented dorsorostrally and peripheral vision ventrocaudally in both nuclei. Terminations in IPm from Area MT are particularly dense. None of these visual areas projects to IPp. Rather, input to IPp appears to originate in cortex rostral to Area MT in the temporal lobe.
Projections of the cerebellar and dorsal column nuclei upon the inferior olive in the rhesus monkey: An autoradiographic study
Authors: Kalil Katherine 
Published: January 2005

AbstractProjections from the cerebellar and dorsal column nuclei to the inferior olive of the rhesus monkey were traced with anterograde autoradiographic methods.The cerebellar nuclei give rise to a massive projection which reaches the contralateral inferior olivary complex by way of the descending limb of the superior cerebellar peduncle. Dentato‐olivary fibers project exclusively upon the principal olivary nucleus (PO) and observe a strict topography. The dorsal, lateral, and ventral dentate project respectively to the dorsal, lateral, and ventral lamellae of the PO. Within the lamellae, the dentato‐olivary fibers are related point for point in the medio‐lateral axis. By contrast, the rostro‐caudal topography is reversed so that the rostral pole of the dentate projects to the caudal PO and the caudal dentate to the rostral PO. These connections are predominantly crossed but a small ipsilateral component recrosses the midline at the olivary commissure and mirrors the topography on the opposite side. The anterior interpositus projects only to the medial half of the DAO and the posterior interpositus projects only to the rostral two thirds of the MAO. The ipsilateral component is minor in comparison with the contralateral projection, but appears to be more substantial than the ïpsilateral projection to the PO arising from the dentate nucleus. The fastigial nucleus does not project upon the olivary complex.The dorsal column nuclei project topographically upon the contralateral accessory nuclei with the gracile nucleus sending fibers primarily to the lateal half of the DAO and the cuneate nucleus projecting to rostral cell groups of the MAO.The present results when compared with other olivary connections described by previous studies in a veriety of species suggest that regions of the MAO and DAO receiving sensory information from the periphery may lie outside the influence of cerebellar feedback loops.
Commissural projections of the cortical hand motor area in monkeys
Authors: Jenny A. B. 
Published: January 2005

AbstractThe topographical organization of the contralateral cortical projections of the motor hand area was studied with autoradiographic methods in 11 macaque monkeys.Two general observations were noted in the material studied. (1) The commissural cortico‐cortical connections of the motor hand area were directed to the contralateral precentral gyrus. The projections were preferentially directed to both homotopic and non‐homotopic areas. (2) Focally labeled areas of motor cortex (diameter 900 μm) gave rise to individual terminal columns of label (diameter 600–900 μm). Larger areas of labeled motor cortex, (3,000 μm in diameter) gave rise to contralateral terminal bands of label. These bands (600–1,000 μm in width) were oriented in an antero‐posterior direction and appeared to be formed by a sequence of adjacent labeled columns.
Development of the diencephalon in the rat. V. Thymidine‐radiographic observations on internuclear and intranuclear gradients in the thalmus
Authors: Altman Joseph , Bayer Shirley A. 
Published: January 2005

AbstractGroups of pregnant rats were injected with two successive daily doses of 3H‐thymidine from gestational days 13 and 14 (E13 + 14) until the day before birth (E21 + 22). Internuclear and intranuclear cytogenetic gradients were examined in radiograms of the thalamus sectioned in the coronal, sagittal and horizontal planes. There was a precise and segregated lateral‐to medial gradient between and within the habenular nuclei. In the ventral thalamus the reticular nucleus had a lateral‐to‐medial gradient, the subthalamic nucleus a laterodorsal‐to‐medioventral gradient. There was a caudal‐to‐rostral gradient between the medial geniculate and dorsal lateral geniculate nuclei, and between the pars posterior and pars anterior of the lateral nucleus. A clear intranuclear gradient could not be detected in the sensory relay nuclei with the exception of the medial geniculate nucleus. A lateral‐to‐medial internuclear gradient was seen between the relay nuclei and the intralaminar nuclei, and between the latter and some of the midline nuclei.On the basis of a consideration of the time of origin and time span of production of neurons of various thalamic nuclei, and taking into account some of the recognizable internuclear and intranuclear gradients, the thalamus was divided into five principal cytogenetic components: the epithalamus, the ventral thalamus, the dorsal thalamus, the medial thalamus, and the posterior thalamus. The epithalamic nuclei form over a protracted period resembling the nuclei of the hypothalamus. The nuclei of the ventral thalamus are generated early and over a relatively long period. The dorsal thalamus consists of the relay nuclei and the intralaminar nuclei; they form rapidly and ahead of the medial thalamus. The medial thalamus was subdivided into the earlier‐forming antero‐medial nuclei and the latest‐forming midline nuclei. The posterior thalamus was not examined in detail.
The cells of origin of the primate spinothalamic tract
Authors: Willis W. D. , Kenshalo D. R. , Leonard R. B. 
Published: January 2005

AbstractSpinothalamic tract cells in the lumbar, sacral and caudal segments of the primate spinal cord were labelled by the retrograde transport of horseradish peroxidase (HRP) injected into the thalamus. The laminar distribution of stained spinothalamic cells in the lumbosacral enlargement differed according to whether the HRP was injected into the lateral or the medial thalamus. Lateral injections labelled cells in most laminae, but the largest numbers of cells were in laminae I and V. The highest concentrations of cells labelled from the medial thalamus were in laminae VI‐VIII. Ninety percent or more of the stained spinothalamic cells in the lumbosacral enlargement were contralateral to the injection site. In the conus medullaris stained spinothalamic cells were most numerous in laminae I, V and VI following lateral thalamic injections of HRP. Many of the cells of the conus were in Stilling's nucleus. Twenty‐three percent of the cells in the conus were ipsilateral to the injection site in the lateral thalamus. Only a few cells in the conus were labelled by medial thalamic injections. The total number of spinothalamic cells from L5 caudally was estimated to be at least 1,200‐2,500. An injection of HRP into the midbrain resulted in a laminar distribution of labelled cells much like that produced by a lateral thalamic injection. The types of spinothalamic tract cells and the sizes of their somata were determined for different laminae. The cells types resemble those already described from Golgi and other studies of the spinal cord gray matter. The spinothalamic tract cells in lamina I included Waldeyer cells and numerous small fusiform, pyriform or triangular cells. Those in lamina II included limitrophe and central cells. Spinothalamic cells in lamina III were central cells. Most of the labelled cells in laminae IV‐X were polygonal, although there were also flattened cells in these layers. The smallest spinothalamic cells were in laminae I‐III, while the largest were in laminae V and VII‐IX. Spinothalamic cells in the conus medullaris included cells like those in the lumbosacral enlargement, but also a special cell type in Stilling's nucleus. Some cells in the conus had dendrites that crossed the midline. Spinothalamic axons could sometimes be traced to the ventral white commissure within one or a few sections. In longitudinal sections, most labelled axons were in the ventral part of the lateral funiculus on the side of the injection, although a few were in the ventral funiculus or on the contralateral side. The axons were widely dispersed, and a few were located adjacent to the pia‐glial membrane.
The emergence, localization and maturation of neurotransmitter systems during development of the retina in Xenopus laevis. I. γ‐aminobutyric acid
Authors: Hollyfiels Joe G. , Rayborn Mary E. , Sarthy P. Vijay , Lam Dominic M. K. 
Published: January 2005

AbstractThe high‐affinity uptake, biosynthesis and release of GABA have been studied in the retina of Xenopus laevis. In the mature retina, [3H]‐GABA is accumulated predominantly by horizontal cells. A second population of cells located in the inner nuclear layer (possibly a type of amacrine cell) also showed a specific GABA uptake. In addition, this retina contains significant activities of L‐glutamic acid decarboxylase and also releases [3H]‐GABA in response to increasing K+ concentrations in the medium. We have followed the appearance and maturation of these GABA‐ergic properties during embryonic development of this retina. Our results indicate that these properties emerge in a precise temporal pattern during retinal differentiation: the specific neuronal uptake of GABA synthesis which is followed by K+‐stimulated GABA release.
A second type of horizontal cell in the monkey retina
Authors: Kole Helga , Mariani Andrew , Gallego Antonio 
Published: January 2005

AbstractA second type of horizontal cell with a distinctly different appearance from the previously known horizontal cell has been seen in Golgi‐impregnated monkey retinas. The new HII cell has a different dendritic branching pattern from the commonly described HI cell type, and it has a short convoluted axon with collaterals bearing small clusters of terminals. Comparisons of the two cell types at different retinal eccentricities show that HII cells have larger dendritic trees than HI cells in the foveal region but smaller dendritic trees than HIs in peripheral retina. Dendritic terminals of the new HII cell, like the HI cell, contact cone pedicles as lateral elements of the ribbon synapses. The isolated terminals or clusters of terminals borne by the short axon of the HII cell also contact cone pedicles as lateral elements rather than contacting rod spherules as lateral elements like HI terminal arborizations. Thus, the monkey like other vertebrates has at least two horizontal cell types which differ in morphology and synaptic connections.
A mechanism for the guidance and topographic patterning of retinal ganglion cell axons
Authors: Silver Jerry , Sidman Richard L. 
Published: January 2005

AbstractThree dimensional reconstruction, with the use of serial, 1‐μm sections, has revealed a system of oriented intercellular spaces within the undifferentiated optic cup. These large openings appear in the marginal zone of the primitive retina and optic stalk prior to the formation of the first retinal ganglion cell axons. The spaces at the region of the optic disc form sets of long, interconnecting tunnels oriented in the direction of the stalk. The spaces at the back and rim of the cup form blind, radially arranged pockets. The extracellular tunnels of the optic disc region strictly maintain their positions in relation to the optic fissure and, thus, discrete portions of the retina become connected by continuous openings with equivalent regions in the stalk. The path taken by the earliest outgrowing optic fibers is identical to the one previously established by the intercellular tunnels. We propose that the tunnel and pocket layout may provide directional and topographic information to the first forming optic axons.