bluuebunny/crossref_metadata_2025_split huggingface dataset:
Immunohistochemical evidence for transient expression of fibronectin in the developing dorsal lateral geniculate nucleus of the ferret
Authors: Brunso‐Bechtold J. K. , Agee D. , Sweatt A. J. 
Published: January 2005

AbstractIn recent years, the important role of the extracellular matrix in neural development has been increasingly recognized. In order to begin to examine what role might be played by the extracellular matrix in the developing dorsal lateral geniculate nucleus (dLGN), the present study used immunocytochemistry to assess the distribution of a recognized extracellular matrix molecule, fibronectin (FN), during postnatal development of the ferret dLGN. Prior to the segregation of cell layers, no clear pattern of FN distribution can be distinguished within the dLGN. By P16, when layers A and A1 are separated by an interlaminar space, FN is localized in that space. By P24, FN is present not only between layers A and A1, but also within layers A and A1 as bands parallel to the laminar borders. These bands appear to correspond spatially and temporally to the development of sublaminar boundaries in the ferret (Hahm and Sur, Neurosci Abstr 14:460, 1988). By the end of the first postnatal month, immunoreactivity is diminished but still present. FN is no longer present at P44 or in the adult. Adjacent sections were incubated with antiserum to glial fibrillary acid protein (GFAP). When a laminar pattern of GFAP can be distinguished, it coincides with the interlaminar distribution of FN. The findings described here are consistent with a role for FN in the development of a laminar organization in the dLGN.
Substance P innervation of the rat and cat thalamus. II. Cells of origin in the spinal cord
Authors: Battaglia Giorgio , Rustioni Aldo 
Published: January 2005

AbstractEvidence in the preceding paper suggests that fibers and terminals immunopositive for substance P (SP) in somatosensory thalamic nuclei are part of the spinothalamic tract (STT). In this paper, more direct evidence on this point is provided by immunocytochemistry for SP on the cervical spinal cord, alone or combined with the retrograde transport of colloidal gold‐labeled wheat germ agglutinin conjugated to enzymatically inactive horseradish peroxidase (WGAapoHRP‐Au). In cats and rats pretreated with colchicine and/or anterolateral chordotomy (to increase SP content in cell bodies), many small to large cell bodies are SP‐immunopositive especially in laminae I and V, but also in more ventral laminae of the upper cervical cord. SP neurons are also present in the dorsolateral funiculus (in the lateral spinal nucleus, LSN, in rats) but not in the lateral cervical nucleus or in the internal basilar nucleus. In both species there is a considerable degree of overlap in the distribution of SP‐positive neurons and that of STT neurons.SP immunocytochemistry in rats after WGAapoHRP‐Au injection in the somatosensory thalamus reveals SP‐positive STT neurons in LSN, in lamina I and in lamina V, and, to a lesser extent, in more ventral laminae. These results demonstrate that SP is a marker and/or neuromediator for some STT neurons. Together with the evidence discussed in the preceding paper, the results also suggest that SP‐positive neurons may be involved in the transmission of nociceptive input.
Neuropeptide Y‐like immunoreactivity in the diencephalon of the little brown bat (Myotis lucifugus): Localized variations with physiological state
Authors: Laemle Lois K. , Cotter John R. 
Published: January 2005

AbstractThe current study used light microscopic immunocytochemistry to demonstrate and compare neuropeptide Y‐like immunoreactivity (NPY‐IR) in the diencephalon of the little brown bat (Myotis lucifugus) at different stages in its annual cycle of activity and hibernation. Animals were sacrificed in each of three discrete physiological states: euthermic, hypothermic, and hibernating.In general, NPY‐IR was abundant in the hypothalamus and sparse in other diencephalic areas. Immunoreactivity was present in a number of pathways which project to or originate from diencephalic nuclei; these include the ansa peduncularis, medial forebrain bundle, inferior thalamic peduncle, stria terminalis, stria medullaris, mammillary peduncle, and dorsal longitudinal fasiculus. Dense fiber plexuses were present throughout the hypothalamus; however, NPY‐IR was conspicuously absent from the suprachiasmatic nucleus. Immunoreactive perikarya were located in the supraoptic, dorsomedial, ventromedial, and arcuate nuclei, in the external division of the ventral lateral geniculate nucleus, and in the pineal gland. Localized changes in density and/or distribution of NPY‐IR were correlated with changes in physiological state.
Expression of GABA and GABAa receptors by neurons of the subplate zone in developing primate occipital cortex: Evidence for transient local circuits
Authors: Meinecke Douglas L. , Rakic Pasko 
Published: January 2005

AbstractSeveral lines of evidence suggest that the transient subplate zone of the embryonic mammalian telencephalon could influence cortical development through synaptic or trophic interactions with growing cortical afferents and migrating neurons. Since such interactions may involve neurotransmitters and their receptor molecules, we have examined the expression of GABA and subunits of the GABAA/benzodiazepine receptor complex in the occipital lobe of embryonic rhesus monkeys by immunochemistry and in situ hybridization. We found that during the second half of gestation, when the subplate zone reaches peak maturity in this species, many neurons can be immunolabeled with both GABA antisera and monoclonal antibodies against GABAA receptor subunits. The most robust labeling occurs at approximately embryonic day (E)125 (birth is at E165). Electron microscopic observations of receptor subunit‐immunolabeled material confirmed that subunits of the GABAA receptor are localized in the subplate neurons and their dendritic processes. In many instances the reaction product is associated with the plasma membranes of labeled processes, some of which form symmetrical synapses with small unlabeled axon terminals. The results of in situ hybridization are in accord with the results of receptor subunit immunochemistry. From E80 to E141, hybridization signal for GABAA receptor subunit mRNA occurs in the subplate zone and increases steadily to peak levels between E125 and E141. The present results reveal that all the elements necessary for the formation of functional GABAergic synaptic circuitry are present in the subplate zone. Further, the ages showing the most pronounced receptor and transmitter expression in this primate coincide with the ingrowth of major cortical afferent systems. Taken together, these findings suggest that GABAergic local neuronal circuits in the subplate may be involved in the development of long tract connections stationed in this zone prior to their transfer to the overlying cortical plate.
The mosaic of alpha cells in the cat retina is not dependent on axon terminal interactions during development
Authors: Jeffery Glen , Whitmore Alan , Grant Simon 
Published: January 2005

AbstractAlpha ganglion cells in the cat retina are distributed in a regular array. It has been proposed that the development of this mosaic pattern is achieved by class‐specific interactions between the dendrites and/or axon terminals of neighbouring alpha cells, but the relative contributions that are made by each of these factors to the regularity of the mosaic remain unclear. An opportunity to address this question is provided by a comparative study of the distribution of alpha cells across the nasotemporal division of normally pigmented and Siamese cat retinae. In this strip of retina the alpha cell population divides its axon terminals between the two sides of the brain. Hence, the potential for interactions between axon terminals of alpha cells whose somata are adjacent within this region of the retina is undermined. This situation is exacerbated in Siamese cats because they have a congenital abnormality in this region, which results in an abnormally wide nasotemporal division.In this study the regularity of the alpha cell mosaic has been analysed at a wide range of eccentricities, including the nasotemporal division. In normally pigmented cats the nasotemporal division was visualised directly following unilateral horseradish peroxidase injections into the thalamus. In Siamese cats, the location of the abnormally wide nasotemporal division was inferred from electrophysiological recordings undertaken in their striate cortices. In both strains of cat the regularity of the alpha cell mosaic was shown to be largely independent of their density or retinal location. Furthermore, in the normals, the separate mosaics for ipsilaterally or contralaterally projecting alpha cells within the nasotemporal division were found to be no more or less regular than that for the combined population. This finding implies that there is no disturbance in their order across the discontinuity formed by their separate chiasmatic routes. Similar results were obtained from within the abnormal nasotemporal division of the Siamese cat. It is concluded that terminal interactions play an insignificant role in the formation of the adult alpha cell mosaic, the regularity of which is probably established by class‐specific intraretinal Interactions.
Projections from rabbit caudal medulla to C1 and A5 sympathetic premotor neurons, demonstrated with phaseolus leucoagglutinin and herpes simplex virus
Authors: Li Yu‐Wen , Wesselingh S. L. , Blessing W. W. 
Published: January 2005

AbstractWe combined Phaseolus vulgaris leucoagglutinin anterograde tracing and Herpes simplex virus transneuronal retrograde tracing to determine whether neurons in the vasodepressor region of the rabbit caudal ventrolateral medulla project to brainstem neurons containing the virus after its transneuronal transport from the adrenal medulla. Five days after adrenal injection of virus, 764 ± 159 virus‐positive neurons were found bilaterally in the brainstem: 61% in the C1 sympathoexcitatory region of the rostral ventrolateral medulla, 30% in the A5 region, 5% in the parapyramidal region, and 3% in the paraventricular nucleus of the hypothalamus. Many of the virus‐positive neurons in the C1 and A5 areas also contained tyrosine hydroxylase and, in the parapyramidal area, many contained 5‐hydroxytryptamine. After iontophoretic deposit of leucoagglutinin into the vasodepressor region of the caudal ventrolateral medulla, brain regions containing varicose processes labeled with leucoagglutinin included the regions containing virus‐positive neurons. We examined the C1 and A5 regions following injections of both tracers in the same rabbits, leucoagglutinin into the caudal ventrolateral medulla and virus into the adrenal gland. Varicosities containing leucoagglutinin were seen in contiguity with perikarya and dendritic branches of neurons containing HSV1, in both the C1 and A5 regions. Studies also revealed labeled varicosities in contiguity with TH‐containing C1 and A5 neurons. The projection from the caudal medulla to presumed sympathetic premotor neurons in the C1 area, including some C1 cells, represents a potential pathway whereby activity of neurons in the caudal medulla could reduce blood pressure by inhibiting sympathoexcitatory neurons in the rostral medulla.
Synaptic innervation of the giant cerebral neuron in sated and hungry snails
Authors: Chase Ronald , Tolloczko Barbara 
Published: January 2005

AbstractThe giant cerebral neuron (GCN) is a serotoninergic cell that facilitates feeding behaviour in gastropod molluscs. We have examined the morphology of its cerebral arborizations after labelling them by intracelhilar injection of hexamminecobalt. Observations in the light microscope reveal extensive arborizations, with similar overall distributions, in the terrestrial snails Achatina fulica and Rumina decollata. All the major peripheral nerves terminate within the zone covered by the GCN arbor. In a sample of 370 synapses in which the GCN participated, the GCN was identified as the postsynaptic element in every case, thereby establishing the dendritic nature of the cerebral arborizations. A total of approximately 1,000 synapses contacts the GCN, with no evident regional differences in innervation density. The synaptic membrane of the presynaptic profile is characterized by an agglomeration of small clear vesicles and small dense vesicles. At nonsynaptic membranes there are agglomerations of larger dense and dense core vesicles, suggestive of nonsynaptic release. The dendrites of the GCN also contain vesicles. Starvation for five days (Rumina decollata) caused a significant increase in the proportion of curved synapses relative to flat synapses. This might be a plastic change allowing for a greater efficiency of transmission between sensory afferents and the GCN.
Ultrastructure of the horseshoe bat's organ of corti. I. Scanning electron microscopy
Authors: Vater Marianne , Lenoir Marc 
Published: January 2005

AbstractThe organ of Corti of the echolocating horseshoe bat (Rhinolophus rouxi) was investigated with scanning electron microscopy in order to provide a comparison with non‐echolocating mammals.Throughout the cochlea of horseshoe bats, each outer hair cell (OHC) possesses three rows of stereocilia and there are no morphological distinctions among the different rows of OHCs. However, there are morphological differences between different regions along the cochlea. In the lower and upper basal turn, the receptor surfaces of OHCs are characterized by extremely wide W‐shaped stereocilia bundles and wingshaped cuticular plates. The cuticular plates of OHCs of the middle and outermost rows are arranged parallel to each other. Stereocilia length is only 0.8 μm and there is an exaggerated angle of inclination of the shortest row of stereocilia towards the next taller one. Stereocilia arrangements in the apex of the horseshoe bat's cochlea closely resembles those observed in the midbasal region of the rat cochlea.Inner hair cells (IHC) in the lower basal turn appear specialized. They possess only two rows of stereocilia and only 7–8 stereocilia per row. Their cuticular plates are small and oval and widely separated from one another in the longitudinal direction. IHCs at all other locations possess three and up to four rows of stereocilia and 17–20 stereocilia per row. Their cuticular plates are elongated and closely spaced. The transition from specialized to typical mammalian morphology occurs abruptly (over a distance of about 100–150 μm) at the border between the lower and the upper basal turn. This transition is not accompanied by a change in OHC morphology.In the subsurface of the tectorial membrane, throughout the cochlea, there are distinct imprints of the tallest row of stereocilia of all three rows of OHCs and of the IHCs.Data are discussed in relation to specialized aspects of the cochlear frequency map in horseshoe bats and as possible micromechanical adaptations to ultra‐high frequency hearing.
Ultrastructure of the horseshoe Bat's organ of corti. II. Transmission electron microscopy
Authors: Vater Marianne , Lenoir Marc , Pujol Remy 
Published: January 2005

AbstractThe fine structure of the organ of Corti was investigated in the echolocating horseshoe bat (Rhinolophus rouxi) by transmission electron microscopy. Particular emphasis was placed on the receptor cells and their supporting cells.The receptor cells, inner hair cells (IHC) and outer hair cells (OHC), possess the typical mammalian shape, but OHCs are extremely short (length: 12–15 μm in the basal turn and up to 28–30 μm in the apical turn). The afferent innervation of both types of receptor cells and the efferent innervation of the IHC system conform to the general mammalian scheme; however, confirming earlier reports, an efferent innervation to the OHCs is absent. Throughout the cochlea, IHCs and OHCs possess a single layer of subsurface cisternae. Above the level of the nucleus of the OHCs, the arrangements of the subsurface cisternae and their connection to the lateral cell membrane via pillars are highly regular, whereas in IHCs, the cisternae are of irregular shape and the pillar system is much less distinct. In the basal turn of the cochlea, the attachment sites of the OHCs to the supporting cells possess specialized features: (a) in the reticular lamina, the contact sites of the cuticular plates of OHCs with the outer pillar cells and the Deiters cell phalanges are of exaggerated length, and (b) the cup formation of the Deiters cell body, which houses the bottom of the OHC, has a specialized shape and is packed with electron‐dense material and microtubules.The results are discussed in relation to cochlear ultrastructure in other mammals and in the context of active processes in cochlear mechanics.
Direct W‐like geniculate projections to the cytochrome oxidase (CO) blobs in primate visual cortex: Axon morphology
Authors: Lachica E. A. , Casagrande V. A. 
Published: January 2005

AbstractThe primate lateral geniculate nucleus (LGN) is composed of large, medium, and small cells located, respectively, in magnocellular (M), parvocellular (P), and specialized layers (intercalated and S‐layers in simians, koniocellular (K) layers in prosimians). Several studies have examined the physiology and connections of M and P LGN cells and have concluded that they provide separate contributions to visual perception via separate pathways. Less is known about the structure and contributions of the small LGN cells. This study examined the distribution and structure of K LGN cell axons in the cortex of the prosimian, Galago crassicaudatus. Wheat germ agglutinin conjugated to horseradish peroxidase, or Phaseonlus vulgaris leucoagglutinin, was injected into the LGN K layers to demonstrate the overall axon projection pattern and the details of individual axons, respectively. Location of axons within striate cortex was specified relative to boundaries determined by Nissl or cytochrome oxidase (CO) stains on the same or adjacent sections.Our results show that K LGN axons end as single complex arbors within one CO blob zone in layer III; they never terminate in interblob zones. These axons also emit a collateral in layer I that arborizes more broadly and spans both CO blob and interblob zones. These data, together with data on K cell physiology and intralaminar cortical connections, suggest that the LGN small cell pathway could modulate the activity of the other two pathways in striate cortex and contribute directly to visual perception. © 1992 Wiley‐Liss, Inc.
Interphotoreceptor matrix in the human retina: Cone‐like domains surround a small population of rod photoreceptors
Authors: Iwasaki Masayuki , Myers Kathy M. , Rayborn Mary E. , Hollyfield Joe G. 
Published: January 2005

AbstractThe interphotoreceptor matrix (IPM) in mammalian retinas is subdivided into rod and cone specific compartments: peanut agglutinin (PNA) binding glycoconjugates are associated with cones, whereas wheat germ agglutinin (WGA) binding glycoconjugates are associated with rods. To establish the identity of a photoreceptor cell type in the human retina with rod dimensions but with a matrix domain which stains with PNA, double label studies, using PNA‐ferritin to decorate the extracellular domains and immunocytochemical techniques using a rod specific anti‐opsin antibody were conducted. The PNA‐binding domains were observed in the cone‐associated IPM as well as in the IPM surrounding a small population of rod‐shaped photoreceptors. The outer segments of these rod‐shaped photoreceptors showed intense labeling with a rod specific anti‐opsin antibody as did all other rods which were free of PNA‐labeling. A quantitative analysis of all retinal quadrants indicates that this novel rod represents approximately 0.3% of the total rod population in the human retina. © 1992 Wiley‐Liss, Inc.
Spatial organization of the auditory nerve according to spontaneous discharge rate
Authors: Kawase Tetsuaki , Liberman M. Charles 
Published: January 2005

AbstractAuditory‐nerve fibers in mammals have been classified into three functional subclasses according to spontaneous discharge rate (SR). In cat, the peripheral terminals of these SR groups are segregated around the sensory cell circumference (Liberman, '82, Science 216:1239–1241). The present study shows that this spatial segregation is at least partly maintained through the peripheral axonal course from sensory cell to spiral ganglion. Analysis of intracellularly labeled auditory‐nerve fibers shows that peripheral axons and cell bodies of low‐and medium‐SR fibers tend to be found closer to scala vestibuli than high‐SR fibers. Since low‐and medium‐SR fibers tend to be thinner, this SR‐based segregation can also be demonstrated as a fiber‐caliber gradient in the osseous spiral lamina. The issue of SR‐based spatial segregation is relevant to reports that ganglion cells near scala vestibuli project to different regions of the cochlear nucleus than cells near scala tympani (Leake and Snyder, '89, J. Comp. Neurol. 281:612–629). Combining the results of the two studies suggests that there may be some SR‐based spatial segregation of inputs to the cochlear nucleus. © 1992 Wiley‐Liss, Inc.
Ultrastructure of the periaqueductal grey matter of the rat: An electron microscopical and horseradish peroxidase study
Authors: Buma Pieter , Veening Jan , Hafmans Theo , Joosten Henk , Nieuwenhuys Rudolf 
Published: January 2005

AbstractThe neurons of the mesencephalic periaqueductal grey substance (PAG) in the rat are small and medium sized. The cells are frequently located in small clusters, without interdigitating glial elements and may be connected by direct membrane appositions or by gap junctions. The inner zone of the PAG is cell poor. In many cases, the cytoplasm of the cells is filled with extensive rough endoplasmic reticulum, free ribosomes, Golgi apparatus, and large lysosome‐like granules. The nuclei show large indentations. The cells have a high nucleus‐cytoplasm ratio.The neuropil is very extensive and particularly rich in large numbers of small unmyelinated axons, dendrites, axonal varicosities, and synaptic connections. Myelinated fibres are relatively scarce. The orientation of the fibres was studied in transverse and horizontal sections, in combination with HRP track tracing experiments. It appeared that throughout the PAG most of the fibres were orientated longitudinally. Quantitation showed that most fibres were present in the inner zones of the PAG. Moreover, the diameter of the fibres adjacent to the aqueduct was smaller than that of the fibres in the peripheral parts of the PAG. The thin unmyelinated fibres made extensive synaptic connections within the PAG. Many synaptic varicosities were found in the neuropil of the PAG. There were four types of synaptic varicosities, characterized by different populations of clear and dense‐core secretory granules and by the different morphology of the synaptic specializations. In general, the different types of varicosity were homogeneously distributed in the different parts of the PAG. Electron dense secretory granules, when present, were located at some distance from the synaptic junction. Serial sections revealed varicosities which contained only dense‐core secretory granules, without synaptic specializations.The dendrites of PAG neurons generally lacked synaptic spines. Many dendrites, particularly those of neurons located in the peripheral parts of the PAG, were directed toward the aqueduct.The present study shows that the PAG is a very complex brain area. The crisscrossing of axons and dendrites with synaptic connections at considerable distances from the cell bodies render it very difficult to unravel the relationships between the possible sources and destinations of ongoing information. This structure complicates the search for relationships between the functional organization and the cytoarchitectural borders in the PAG area.