bluuebunny/crossref_metadata_2025_split huggingface dataset:
Distribution and morphology of human cone photoreceptors stained with anti‐blue opsin
Authors: Curcio Christine A. , Allen Kimberly A. , Sloan Kenneth R. , Lerea Connie L. , Hurley James B. , Klock Ingrid B. , Milam Ann H. 
Published: January 2005

AbstractPrimate cones maximally sensitive to short wavelength light (blue cones) have been previously identified by using indirect methods. We stained 7 wholemounted human retinas obtained from 6 female donors, using an affinity purified antibody to a 19 amino acid peptide sequence at the N‐terminus of blue opsin (Lerea et al., '89: Neuron 3:367–376), standard PAP immunocytochemistry, and controls. Cones were counted where all outer segments could be traced to inner segments and were measured where cells were well aligned vertically.We find that: (1) 7% of cones within 4 mm of the foveal center are labeled by antiblue opsin; (2) compared to neighboring red/green cones, blue cone inner segments are 10% taller, have a larger cross‐sectional diameter near the junction with the outer segment, and a smaller diameter near the external limiting membrane, resulting in a more cylindrical shape, (3) foveal blue cones are sparse, irregularly spaced, and missing in a zone about 100 μm (0.35°) in diameter near the site of peak cone density, (4) the highest densities of blue cones (> 2,000 cells/mm2) are found in a ring at 0.1–0.3 mm eccentricity, and (5) the shortest distances between neighboring cones are between blue and red/green cones, and the blue and red/green mosaics are statistically independent.These findings are consistent with psychophysical reports of foveal tritanopia and maximum sensitivity to blue light at 1° eccentricity. Blue cone spacing may limit resolution of the blue channel out to 20–30° eccentricity. The blue and red/green mosaics appear to be formed by separate processes.
Horizontal optokinetic nystagmus in unilaterally enucleated pigmented rats: Role of the pretectal commissural fibers
Authors: Reber Annie , Sarrau Jean Marie , Carnet Janick , Magnin Michel , Stelz Thérèse 
Published: January 2005

AbstractMonocular enucleation reduces the asymmetry of horizontal optokinetic nystagmus (H‐OKN) in afoveate mammals by increasing responses to nasotemporal visual stimulation. The origin of these larger responses was investigated in adult pigmented rats monocularly enucleated as neonates or as adults by analyzing retinal and commissural projections to the deafferented nucleus of the optic tract (NOT) and the functional role of this nucleus before and after section of the posterior commissure.Anatomically, monocular enucleation reduces the volume of the contralateral deafferented NOT. Anterograde tracers injected in the intact eye reveal a crossed projection of the retina to the NOT and to the dorsal (DTN) and medial (MTN) terminal nuclei of the accessory optic system as in normal rats. In addition, there is an uncrossed projection to the MTN in the rats enucleated as neonates. Retrograde tracer injected in the deafferented NOT confirms the absence of an uncrossed retinal projection but reveals connections between both NOT via the posterior commissure as in normal rats.Electrophysiologically, the larger nasotemporal optokinetic responses in monocularly enucleated rats return to normal after posterior commissurotomy.This study demonstrates that no anatomical remodelling takes place to increase nasotemporal responses in monocularly enucleated rats. The larger responses must then result from functional changes. The role of exclusive contralateral projections of the retina to the NOT and of the commissural connections in mediating the asymmetry of the optokinetic nystagmus in afoveate mammals is discussed.
Expression of a neurally related laminin binding protein by neural crest‐derived cells that colonize the gut: Relationship to the formation of enteric ganglia
Authors: Pomeranz Howard D. , Sherman Diane L. , Smalheiser Neil R. , Tennyson Virginia M. , Gershon Michael D. 
Published: January 2005

AbstractIn order to give rise to the enteric nervous system (ENS), cells migrating from the neural crest must find the bowel and cease migrating at appropriate locations within the gut. Previous studies of the development of the ENS in a mutant mouse have led to the hypothesis that laminin in the enteric mesenchyme may act as a signal to crest‐derived cells to cease migrating and extend neurites (or glial processes). Implied in this hypothesis is the idea that crest‐derived cells, as a prelude to their participation in ganglion formation, acquire a neurally related laminin receptor, which they do not express at pre‐enteric stages of migration. As a partial test of this hypothesis, single and double label immunocytochemistry at light and electron microscopic (EM) levels were used to study the expression of cell surface laminin binding proteins by crest‐derived cells in the process of migrating to or within the developing chick gut. Two antibodies (called 3070 and α‐110) raised against neuronal cell surface laminin binding proteins were employed for this purpose. Laminin binding protein immunoreactivity was found to be expressed within the bowel and ganglion of Remak by a subset of crest‐derived cells (identified immunocytochemically with NC‐1/HNK‐1 antibodies) and by all of those developing as neurons (identified immunocytochemically with antibodies to neurofilament‐associated proteins). Laminin binding protein immunoreactivity was also found to be expressed in fixed neural structures elsewhere in the embryos, including cranial and spinal roots, nerves, and ganglia. In contrast, laminin binding protein immunoreactivity was not expressed by migrating crest‐derived cells in the vicinity of the vagal or sacral regions of the neuraxis (from which the precursors of the ENS take origin); nor was it expressed by juxta‐pharyngeal vagal crest‐derived cells migrating to the foregut through the caudal branchial arches or by the caudal stream of sacral crest‐derived cells approaching the hindgut. EM immunocytochemistry confirmed that laminin binding protein immunoreactivity in the bowel was located on the surfaces of crest‐derived cells, and was exhibited both by those cells that could only be distinguished from their neighbors by their NC‐1/HNK‐1 immunoreactivity and by cells developing as neurons or glia. EM immunocytochemistry also revealed that the surfaces of crest‐derived cells migrating through the enteric mesenchyme were contacted by many small osmiophilic “puffs” of laminin‐immunoreactive extracellular material. These puffs coincided in location with membrane sites that expressed the immunoreactivity of the laminin binding protein. These observations are consistent with the hypothesis that laminin plays a role in the formation of enteric ganglia.
Projections of the tectospinal tract to the upper cervical spinal cord of the cat: A study with the anterograde tracer PHA‐L
Authors: Rose P. K. , MacDonald J. , Abrahams V. C. 
Published: January 2005

AbstractThe goal of the present experiments was to re‐examine the spinal projections of neurons in the superior colliculus (SC) of the cat by taking advantage of the high sensitivity of the anterograde tracer, phaseolus vulgaris leucoagglutinin (PHA‐L). In seven experiments, multiple injections of PHA‐L into different regions of the SC labelled a total of 172 axons in the predorsal bundle; yet only 11 tectospinal tract (TST) axons were found in the upper cervical spinal cord. Collaterals emerging from these axons were rare and arose exclusively from TST axons with a diameter of less than 1 μm. Individual collaterals had different termination zones: some terminated in the lateral part of lamina V and VI after taking a dorsolateral course through lamina VII and VIII; others terminated in the medial part of lamina VII. One collateral terminated within lamina IX and the ventral part of lamina VIII. The combined termination of all collaterals was densest in lamina VII and dorsal lamina VIII. A small number of boutons were also found in the lateral parts of laminae V and VI, and in lamina IX and immediately adjacent regions in lamina VIII. Compared to axons belonging to other spinal descending systems, individual TST axons give rise to much simpler intraspinal collaterals with relatively few boutons. This feature, together with the relative paucity of TST axons, suggests that direct connections from the SC to neurons in the upper cervical spinal cord are sparse. Furthermore, our results are consistent with electrophysiological studies that show that few, if any, neck motoneurons receive monosynaptic connections from TST neurons. Projections to neck motoneurons must therefore involve a relay, either through other descending pathways, such as the reticulospinal system, or via local segmental interneurons.
Differential immunochemical markers reveal the normal distribution of brain macrophages and microglia in the developing rat brain
Authors: Milligan Carolanne E. , Cunningham Timothy J. , Levitt Pat 
Published: January 2005

AbstractBrain macrophages and microglia play important roles in central nervous system (CNS) development, especially during regressive events in which particular neuronal and glial constituents are eliminated. The purpose of this study is to provide a complete map of brain macrophage and microglia distribution in all regions of the neuraxis from birth to sexual maturity. We have utilized morphology and immunostaining with the specific antibodies OX‐42 and EDI to distinguish between brain macrophages and microglia. Brain macrophages are large, round cells, 10–15 μm in diameter, with few or no cytoplasmic processes; these cells are EDI‐ and OX‐42‐immunopositive. Microglia have small cell bodies with numerous, ramified cytoplasmic processes. These cells are OX‐42‐positive, and ED1‐negative. We found a specific pattern of distribution of brain macrophages, targeting specific cortical and subcortical areas transiently, including developing fiber tracts. These cells disappeared completely by the third postnatal week. In contrast, OX‐42‐positive microglia exhibited a gradual increase in number and were distributed uniformly throughout gray matter and within white matter tracts. These cells remain in the adult CNS, constituting the resident microglia population. We suggest that these two distinct phagocytic cell populations perform unique functions in the developing brain, including remodeling of restricted CNS areas by brain macrophages that is part of a normal morphological process.
Effects of hypothyroidism upon the granular layer of the dentate gyrus in male and female adult rats: A morphometric study
Authors: Madeira M. D. , Cadete‐Leite A. , Andrade J. P. , Paula‐Barbosa M. M. 
Published: January 2005

AbstractThe effects of hypothyroidism upon the structure of the central nervous system of adult rats are poorly understood in spite of evidence that the mature brain is vulnerable to this condition. Existing developmental studies show that the morphological changes induced by thyroid hormone deficiency are related to alterations in neurogenesis. We studied the granular layer of the dentate gyrus under different experimental conditions of hypothyroidism, because in rodents the neurogenesis of the granule cells continues during adulthood. The following groups of rats were analysed: (1) control; (2) hypothyroid from day 0 until day 180 (hypothyroid group); (3) hypothyroid until day 30 and thenceforth maintained euthyroid (recovery group); and (4) hypothyroid since day 30 (adult hypothyroid group). Groups of 6 male rats and 6 female rats were analysed separately. The volume of the dentate gyrus granular layer and the numerical density of its neurons were evaluated, so we were able to estimate the total number of granule cells.Because in the experimental groups the volume of the granular layer and the numerical density of its neurons were reduced, the total number of granule cells was decreased. In the hypothyroid and recovery groups the alterations were identical and more striking than in the adult hypothyroid groups. The total number of granule cells displayed sexual differences in all groups studied except in the hypothyroid groups.The present results support the view that thyroid hormone deficiency interferes with the process of cell acquisition by reducing neuronal proliferation and that it also leads to increased cell death. These events underlie the irreversible morphological changes observed in the brain of hypothyroid rats, either during development or at maturity. The referred structural alterations are probably related to the functional deficits observed in this condition.
Developmental expression of neural cell adhesion molecules in the mouse neocortex and olfactory bulb
Authors: Chung Wen‐Wei , Lagenaur Carl F. , Yan Yimin , Lund Jennifer S. 
Published: January 2005

AbstractPolyclonal antibodies to N‐CAM and L1 and monoclonal antibodies to epitopes of N‐CAM (designated 12F11, 8A2, and 12F8) were used to investigate the spatial and temporal distribution of these neural cell adhesion molecules during the development of mouse cortex and olfactory bulb. The aim of the study was to correlate developmental events such as cell migration, dendritic and axonal outgrowth, and synaptogenesis with the appearance and disappearance of specific molecules involved in cell‐cell interactions. Western transfer studies indicated that 12F8 antibody recognized polysialic acid found on embryonic N‐CAM; 8A2 antibody primarily recognized the 140 kD component of N‐CAM while the 12F11 antibody recognized the 180 and the 140 kD forms. The study demonstrates a high degree of cell surface molecular specialization of different compartments in developing neocortex and olfactory bulb. L1 is found on a variety of unmyelinated fiber tracts including thalamocortical fibers, olfactory nerve, and inner plexiform layer of the olfactory bulb. In contrast, N‐CAM epitope recognized by 12F11 antibody is present on olfactory nerve fibers but appears later and is much weaker than L1 on thalamocortical fibers and is absent from the olfactory lobe inner plexiform layer. Dendritic regions are best labeled by 12F8 antibody; the epitope becomes faint in adult cortex but remains strongly expressed in olfactory bulb. This study reveals that widespread N‐CAM expression in the central nervous system is constituted by a diversity of local expression of different molecular forms of N‐CAM; their different anatomical distributions suggest they may each have unique roles.
The sensory epithelium and its innervation in the mole rat cochlea
Authors: Raphael Yehoash , Lenoir Marc , Wroblewski Romuald , Pujol Remy 
Published: January 2005

AbstractThe mole rat (Spalax ehrenbergi) burrows throughout its life in subterranean tunnels. Several structural and functional features which adapt the mole rat to its habitat have been discerned. The goal of this study was to elucidate the structural basis for adaptation of the auditory end‐organ to an environment where low‐frequency acoustical signals prevail. For this purpose, cochleae of adult mole rats were studied with light and electron microscopy. Inner hair cells throughout the cochlea, and outer hair cells in the basal (high‐frequency) portion of the cochlea, were similar in structure to those seen in other mammals. In contrast, outer hair cells in the apical (low‐frequency) portion displayed unique structural features. These features resembled the structure of inner hair cells or immature outer hair cells. The innervation of outer hair cells was most uncommon, in that classical medial efferent innervation was not found throughout the cochlear spiral.
Morphology of intracellularly labeled canine intracardiac ganglion cells
Authors: Xi X. , Randall W. C. , Wurster Robert D. 
Published: January 2005

AbstractThe purpose of this study was to determine the morphological organization and structure‐function correlation of mammalian intracardiac ganglion cells. Conventional intracellular microelectrode techniques were applied to the tissue whole mount preparation of canine intracardiac ganglia. Forty neurons were intracellularly recorded and labeled by means of horseradish peroxidase iontophoresis. Cell morphology was quantitatively analyzed by light microscopy and camera lucida technique. Somata were elongated (mean 62 × 40 μm) and had 2–12 primary dendrites restricted within the ganglion. Almost half of the neurons had either a short axon that was traced only within the ganglion or no axon distinguishable. These neurons may have perhaps been intraganglionically active neurons. The other cells had a long axon that either coursed out of the ganglion to peripheral cardiac tissue or exited the ganglion via interganglionic nerve to innervate more remote cardiac tissue or cells in other intracardiac ganglia. Interaction between neurons was suggested by the close proximity of processes from different neurons. Previously defined electrophysiological cell types (R‐, S‐, and N‐cells), which were significantly different in their passive and active membrane properties, had different morphological features of the somata but not the axonal or dendritic processes. Intra ganglionic or long axon neurons were not associated with a particular electrophysiological cell type. These findings provide the possibility of ganglionic modulation of vagal efferent activity in mammalian heart and also provide some morphological basis for the electrophysiological cell types.
Development of the projections from the dorsal lateral geniculate nucleus to the lateral suprasylvian visual area of cortex in the cat
Authors: Tong Lillian , Kalil Ronald E. , Spear Peter D. 
Published: January 2005

AbstractIn the study reported in the preceding paper, we used retrograde labeling methods to show that the enhanced projection from the thalamus to the posteromedial lateral suprasylvian (PMLS) visual area of cortex that is present in adult cats following neonatal visual cortex damage arises at least partly from surviving neurons in the dorsal lateral geniculate nucleus (LGN). In the C layers of the LGN, many more cells than normal are retrogradely labeled by horseradish peroxidase (HRP) injected into PMLS cortex ipsilateral to a visual cortex lesion. In addition, retrogradely labeled cells are found in the A layers, which normally have no projection to PMLS cortex in adult cats. The purpose of the present study was to investigate the mechanisms of this enhanced projection by examining the normal development of projections from the thalamus, especially the LGN, to PMLS cortex. Injections of HRP were made into PMLS cortex on the day of birth or at 1, 2, 4, or 8 weeks of age. Retrogradely labeled neurons were present in the lateral posterior nucleus, posterior nucleus of Rioch, pulvinar, and medial interlaminar nucleus, as well as in the LGN, at all ages studied. Within the LGN of the youngest kittens, a small number of retrogradely labeled cells was present in the interlaminar zones and among the cells in the A layers that border these zones. Such labeled cells were virtually absent by 8 weeks of age, and they are not found in normal adult cats. Sparse retrograde labeling of C‐layer neurons also was present in newborn kittens. The density of labeled C‐layer neurons increased 5‐ to 10‐fold between 1 day and 1 week of age and then increased further to adult values by 4 weeks of age. These results indicate that there is not an exuberant projection from the C layers of the LGN to the PMLS cortex in young kittens. This suggests, therefore, that the enhanced projection from the C layers to PMLS cortex after an early visual cortex lesion, described in the preceding paper, is due to new axonal growth. In contrast, at least part of the enhanced projection from the A layers after an early visual cortex lesion may result from the retention of an initially transient projection from the interlaminar zones and immediately adjacent cells in the A layers.
Immunocytochemical demonstration of salmon GnRH and chicken GnRH‐II in the brain of masu salmon, Oncorhynchus masou
Authors: Amano Masafumi , Oka Yoshitaka , Aida Katsumi , Okumoto Naoto , Kawashima Seiichiro , Hasegawa Yoshihisa 
Published: January 2005

AbstractWe have recently developed sensitive and specific radioimmunoassays (RIAs) for salmon gonadotropin‐releasing hormone (sGnRH) and chicken GnRH‐II (cGnRH‐II) and have measured the contents of both GnRHs in the rainbow trout brain. Our results showed that contents of the two GnRHs are variable among different brain regions. Therefore, in order to confirm the differential distribution of the two GnRHs by a different technique, we examined the distribution of immunoreactive sGnRH and cGnRH‐II in the brain of masu salmon by using immunocytochemical techniques.sGnRH immunoreactive (ir) cell bodies were scattered in the transitional areas between the olfactory nerve and the olfactory bulb, the ventral olfactory bulb, between the olfactory bulb and the telencephalon, the ventral telencephalon, and the preoptic area. These sGnRH‐ir cell bodies were dispersed in a strip‐like region running rostrocaudally in the most ventral part of the ventral telencephalon. sGnRH‐ir fibers were distributed in the various brain regions from the olfactory bulb to the spinal cord. They were especially abundant in the olfactory bulb, ventral telencephalon, preoptic area, hypothalamus, deep layers of the optic tectum, and thalamus. sGnRH‐ir fibers also innervated the pituitary directly.cGnRH‐II‐ir cell bodies were found in the nucleus of the medial longitudinal fasciculus (nMLF). The distribution of cGnRH‐II‐ir fibers was similar to that of sGnRH‐ir fibers, except that cGnRH‐II‐ir fibers were absent in the pituitary. The number of cGnRH‐II‐ir fibers was much fewer than that of sGnRH‐ir fibers.The results of the present immunocytochemical study are in basic agreement with those of our previous RIA study. Thus, we suggest that in masu salmon, sGnRH not only regulates gonadotropin (GTH) release from the pituitary but also functions as a neuromodulator in the brain, whereas cGnRH‐II functions only as a neuromodulator.
Afferents to the medial nucleus of the trapezoid body and their collateral projections
Authors: Kuwabara N. , DiCaprio R. A. , Zook John M. 
Published: January 2005

AbstractCells and axons that supply direct afferent input to the medial nucleus of the trapezoid body are described. Afferents were intracellularly labeled in brainstem tissue slices of two rodent and two bat species. The main afferents are calyciferous axons from globular bushy cells of the ventral cochlear nucleus. Calyciferous axons were highly consistent across species, projecting directly from the cochlear nucleus, across the midline in the trapezoid body, to the contralateral medial nucleus of the trapezoid body. Within the target nucleus, a typical axon turned sharply away from horizontal to form a large ending, the calyx of Held, around the soma of a single principal cell. Three groups of calyciferous axons were classified based on the path taken from bend to calyx.In subjects younger than four weeks, single axons often formed two calyces, each on a different cell. These calyx pairs were often found on adjacent or vertically aligned cells. In older animals, calyx pairs were more closely aligned, but fewer double calyx axons were seen.A secondary focus of this study was the system of thin collateral branches that characterizes calyciferous axons in all species. The projection patterns of these collaterals suggest that calyciferous axons may provide ascending input to periolivary cell groups with descending projections.In addition to calyciferous afferents, labeled cells that provide input to the medial nucleus of the trapezoid body from adjacent periolivary cell groups are described. Also described is a type of afferent that descends from the level of the lateral lemniscus to the medial nucleus of the trapezoid body.