bluuebunny/crossref_metadata_2025_split huggingface dataset:
Banding of lateral superior olivary nucleus afferents in the inferior colliculus: A possible substrate for sensory integration
Authors: Shneiderman Amiram , Henkel Craig K. 
Published: January 2005

AbstractIn this study the organization of the projection from the lateral superior olivary nucleus (LSO) to the inferior colliculus was investigated in the cat by using anterograde tract‐tracing techniques. The findings indicated that LSO projected bilaterally to the central nucleus of the inferior colliculus as well as to the ventrolateral and rostral pole nuclei. In the central nucleus a larger medial component of the projection ended in pars medialis and centralis. A smaller lateral component ended in the region of the pars lateralis. Both components of the projection appeared to be topographically organized, but in the lateral component the low‐frequency part of LSO appeared to have greater representation.The uncrossed and crossed LSO projections to the inferior colliculus exhibited several important differences in their distribution. First, periodic bands of dense labeling were more prominent in the distribution of the uncrossed projection. The bands measured 150–200 μ in thickness and in some cases interruptions or gaps were present along the length of the bands. The distribution of the crossed projection was more diffuse, but some banding was also apparent. Second, the positions of the bands of dense labeling on the two sides were not homotopic as determined by labeling projections from the ipsilateral and contralateral LSO in the same tissue. The dense bands labeled with WGA‐HRP from an injection in LSO on one side and bands labeled with 3H‐leucine from an injection in LSO on the other side either were interdigitating or were only partially overlapping. Finally, the area over which the uncrossed projection distributed endings varied in size with respect to that of the crossed projection. The variation in size of the area of the projections was a function of the frequency representation. A model based on the three‐dimensional reconstruction of bands as projection sheets is proposed as a substrate for selective integration of afferents in the inferior colliculus.
Spinomesencephalic tract: Projections from the lumbosacral spinal cord of the rat, cat, and monkey
Authors: Yezierski Robert P. 
Published: January 2005

AbstractAnterograde transport of wheat germ agglutinin conjugated to horseradish peroxidase was used to determine the terminal domain of the projection from the lumbosacral spinal cord to the midbrain in the rat, cat, and monkey. Results have shown that several midbrain regions receiving afferent input from this level of the spinal cord are common to the three species examined. Structures innervated by this projection were located throughout the full rostrocaudal extent of the midbrain. The strongest projections were to the intercollicular region and caudal midbrain contralateral to injection sites in the spinal cord. Terminal labeling in the rostral midbrain, except that observed in the nucleus of Darkschewitsch, was substantially less than that observed at more caudal midbrain levels. Structures receiving the strongest input from the spinal cord included the central gray, nucleus cuneiformis, the deep and intermediate layers of the superior colliculus, and the intercollicular nucleus. Other structures receiving afferent input from the lumbosacral spinal cord included the anterior and posterior pretectal nuclei, red nucleus, Edinger‐Westphal nucleus, interstitial nucleus of Cajal, and the mesencephalic reticular formation. It is concluded that the spinal projection to the midbrain is a multicomponent projection consisting of several pathways terminating in discrete midbrain regions. Considering the diverse functions associated with midbrain regions receiving spinal input and the response and receptive field properties of cells belonging to this pathway, the results of the present study are discussed in relation to the potential role of the spinomesencephalic tract in somatic, visceral, and motor function.
Synaptic organization of cholinergic amacrine cells in the rhesus monkey retina
Authors: Mariani Andrew P. , Hersh Louis B. 
Published: January 2005

AbstractIn the rhesus monkey retina, choline acetyltransferase (ChAT) immunoreactivity has been used to study the localization and synaptic organization of cholinergic neurons by both light and electron microscopy with peroxidase‐antiperoxidase immunohistochemistry. ChAT‐containing neurons are a type of amacrine cell with 97.5% of their cell bodies localized to the ganglion cell layer and the remainder in the inner nuclear layer. Their processes arborize in a single narrow band in the inner plexiform layer in a plane diving the outer two‐thirds from the inner one‐third of this synaptic region. With electron microscopy, ChAT‐immunoreactive amacrine cell processes were observed to be primarily postsynaptic to the diffuse invaginating cone bipolar cells and presynaptic to ganglion cells, although they are both post‐ and presynaptic to immunohistochemically unlabeled amacrine cell profiles and to ChAT‐containing amacrine cell processes as well.
Monoclonal antibodies react with neuronal subpopulations in the human nervous system
Authors: Hinton David R. , Henderson Victor W. , Blanks Janet C. , Rudnicka Maria , Miller Carol A. 
Published: January 2005

AbstractMonoclonal antibody probes were used to identify antigenic cross reactivities among neuronal subpopulations and to dissect the human nervous system at several levels of organization. Six monoclonal antibodies, prepared with immunogens from Drosophila melanogaster or human nervous tissue, were used to localize antigens immunocytochemically in normal adult human neocortex, hippocampus, cerebellum, spinal cord, and retina. Four of the six antibodies were neural specific in their reactivity and each stained a unique combination of neurons. The antibodies reacted with at least three subpopulations of cerebral cortical neurons, including discrete populations of pyramidal and nonpyramidal cells. Components of a widely distributed functional system within the spinal cord and cerebellum were labelled by one antibody, which reacted with neurons in the nucleus dorsalis of Clarke, deep cerebellar nuclei, and Purkinje cells. At the single‐cell level, three of the monoclonals differentially labelled the photoreceptor cell outer segment, inner segment, and perikaryon. Three of the six antibodies were reactive with specific protein bands, on immunoblots of tissue homogenates. This monoclonal antibody panel provides a novel and potentially useful method of analysis of the organization of the normal and diseased human nervous system.
Topologic and connectional analysis of the dorsal thalamus of Triturus alpestris (Amphibia, Urodela, Salamandridae)
Authors: Wicht Helmut , Himstedt Werner 
Published: January 2005

AbstractA morphological and connectional analysis was performed on the dorsal thalamus of the alpine newt, Triturus alpestris. We have used a graphic reconstruction technique for the evaluation of the connectional (HRP) data. On the basis of these reconstructions, we propose a subdivision of the salamandrid dorsal thalamus into subhabenular, anteroventral, and posterodorsal zones. Each of these zones is defined by its telencephalic projections (“ascending thalamofugal systems”). The posterodorsal zone projects to the striatum, the anteroventral zone to the pallium. The subhabenular zone projects to the subpallial telencephalon and to the tegmentum. This zonal subdivision allows a more detailed comparison of the salamandrid dorsal thalamic features with ranid dorsal thalamic structures. We compare our dorsal thalamic zones to the ones proposed by Herrick (J. Comp. Neurol. 62:239–261, '35, The Brain of the Tiger Salamander. Chicago: The University of Chicago Press, ′48). Furthermore, using the same reconstructive technique, we undertook an analysis of the spatial relations of various inputs to the salamandrid dorsal thalamus (“thalamopetal systems”) Besides the well‐known retinal inputs, we identified the tectum and the tegmentum as sources of inputs to the thalamus. We provide evidence that there is no extensive multi‐ or unimodal overlap of these thalamopetal systems.
Developmental changes in density and distribution of serotoninergic fibers in the chick spinal cord
Authors: Kojima Tokuzo , Homma Shunsaku , Sako Hiroko , Shimizu Iwao , Okada Akira , Okado Nobuo 
Published: January 2005

AbstractDevelopmental changes of serotoninergic innervation in the chick spinal cord (third lumbosacral segment) were examined with an immunohistochemical technique using an antiserum to serotonin.In the 1‐day‐old hatched chick, serotoninergic fibers were located in laminae I, II, VII, IX, and X. A large number of serotonin‐positive fibers and terminals were found around somal profiles of large neurons and in the neuropil of the medial and lateral parts of the lateral motor column (LMC).In the 1‐week‐old chick, the density of serotoninergic fibers was greatly increased in the posterior columns, and serotoninergic fibers were most densely aggregated in the dorsolateral part of the LMC.In the 2‐week‐old chick, a considerable decrease in the density of serotoninergic fibers was observed in the lateral funiculus and the gray matter (laminae I, II, VII, IX, and X). In the LMC, serotonin‐positive fibers and terminals were largely absent from the neuropil, but were found preferentially around the somal profiles of large neurons. Between 1 and 2 weeks after hatching the density of varicosities and terminals in the neuropil of the dorsolateral and medial parts of the LMC decreased by 33% and 56%, respectively.In the 3‐month‐old chick, the density of serotoninergic fibers in laminae I, II, V, VII, and X had increased compared to younger ages. Serotonin‐positive fibers were not evenly distributed in the LMC of the adult chicken; rather, they were densely aggregated around the soma and proximal dendrites of motoneurons in the dorsolateral LMC. Many neuronal soma in the medial and intermediate regions of the LMC lacked serotoninergic fibers.
Immunohistochemical study of glutaminase‐containing neurons in the cerebral cortex and thalamus of the rat
Authors: Kaneko Takeshi , Mizuno Noboru 
Published: January 2005

AbstractIn an attempt to identify glutamatergic neurons, the cerebral cortex and thalamus of the rat were examined immunohistochemically by using a monoclonal antibody against phosphate‐activated glutaminase (PAG), a major synthetic enzyme of transmitter glutamate in the central nervous system. In both the neocortex and mesocortex, pyramidal cells in layers V and VI showed intense PAG‐like immunoreactivity (PAG‐LI), whereas neuronal cell bodies in layers I–IV showed weak PAG‐LI. At the deep border of layer VI, neurons with horizontally elongated cell bodies showed PAG‐LI. In the pyriform and entorhinal cortices, neurons with intense to moderate PAG‐LI were seen in layer II as well as in the deeper layers. In the hippocampal formation, pyramidal cells in CA1, CA2, and CA3 and polymorphic cells in CA4 showed PAG‐LI; PAG‐LI was most intense in pyramidal cells of CA3. Fine granules with weak PAG‐LI were also seen on and/or within the cell bodies of granule cells in the dentate gyrus. In the thalamus, neurons with PAG‐LI were distributed in all nuclei, although regional differences were observed in the distribution pattern of neurons with PAG‐LI and in the intensity of PAG‐LI in individual neurons. The largest neurons in each thalamic nucleus showed intense PAG‐LI; these were considered to be projection neurons. In addition to perikaryal labeling, many fine, PAG‐like immunoreactive granules were distributed in the neuropil of both the cerebral cortex and thalamic nuclei. Some of these fine granules with PAG‐LI in the neuropil were assumed to represent fiber terminals with PAG‐LI, because the distribution pattern of the deposits in the primary somatosensory and primary visual cortices resembled that of thalamocortical fiber terminals.Glutamate is rather ubiquitous in the mammalian central nervous system, and it is still debatable whether the monoclonal antibody to PAG from brain mitochondria can distinguish transmitter‐related glutaminase from the other metabolism‐related ones. In the present study, however, large neurons in the thalamic nuclei, as well as pyramidal neurons in the cerebral cortex, showed PAG‐LI most intensely, supporting the assumption that projection neurons of the cerebral cortex and thalamus are primarily glutamatergic.
Asymmetric distribution of retinal ganglion cells in goldfish
Authors: Mednick Adam S. , Springer Alan D. 
Published: January 2005

AbstractThe distribution of retinal ganglion cells (RGCs) in goldfish was determined by removing an eye and applying cobaltous‐lysine to the optic nerve for 24 hr. This procedure allowed the cobalt label to be in continuous contact with the cut ends of the optic axons and thereby backfilled many RGCs. RGC density was determined across three different sizes of retinae by using fish with different eye sizes.Confirming earlier work, we found that RGC density diminished as retinal area increased. However, irrespective of the retinal size, the density of RGCs was elevated along the temporal boundary between the dorsal and the ventral retina. A conservative estimate indicated that the RGC density in the temporal retina was at least 1.8–2.5 times higher than the mean RGC density of the entire retina. Thus, the goldfish retina does not appear to have a homogeneous distribution of RGCs as was previously considered.Small and large retinae differed with respect to the percentage of cells in the RGC layer that was RGCs. In small retinae, even when the noncobaltfilled cells (glia and displaced amacrine cells) were added to the cobalt‐filled RGCs, the density of all cell types was elevated in the temporal retina relative to the remainder of the retina. Furthermore, in small retinae, the percentage of cells in the RGC layer that was RGCs (75%) was constant across the radial and circumferential aspects of the retina. In marked contrast, in medium‐large retinae, a homogeneous distribution of cells across the entire retina resulted when the noncobalt‐filled cells were added to the cobalt‐filled cells. However, the percentage of cells that was cobalt‐filled RGCs was significantly greater in the temporal retina (50%) than in the remainder of the retina (35%). In large retinae, as in small retinae, the percentage of cells that was RGCs did not vary as a function of distance from the optic disc. These data suggest that, in the course of retinal maturation, cell density in the temporal retina is elevated initially and then declines subsequently to the level of the surrounding retina. Over time, more displaced amacrine cells may be added to the tissue surrounding the temporal retina. Alternatively, more RGCs outside the temporal retina may become displaced amacrine cells. Such events could account for the growth‐associated, disproportionate decrease in the percentage of cells that is RGCs in the tissue surrounding the temporal retina.Cobalt‐filled RGCs had a mean somata area of 50 μm2 and ranged in size from 20 to 310 μm2. Temporal and nasal RGCs had the same mean soma areas. Estimates of the total number of RGCs suggested that the number of RGCs increased as the retinal area increased. This relationship was linear in small retinae (i.e., up to 15 mm2). However, progressive twofold increases in retinal area were only accompanied by 20% increases in the number of RGCs. Thus, additional factors, beyond RGC addition at the retinal margin, must account for the expansion of larger retinae.
Ultrastructural evidence that horizontal cell axon terminals are presynaptic in the human retina
Authors: Linberg Kenneth A. , Fisher Steven K. 
Published: January 2005

AbstractThe organization of the rod spherule and of the horizontal cell axon terminals within the invagination of the rod spherule in the human retina was examined in serial sections by electron microscopy. Twenty‐one rod spherules were reconstructed in this study. Axon terminal processes of type I horizontal cells consistently make one or two small punctate synapses onto each rod spherule within the invagination. In addition, these axon terminal processes make distinct synapses upon rod bipolar dendrites outside the spherule before both processes enter the invagination.This is the first positive description of a synapse from a horizontal cell axon terminal process onto a photoreceptor terminal and the first identification of a synapse from a horizontal cell to a rod bipolar cell in the mammalian outer plexiform layer. We speculate that the axon terminal‐to‐rod synapse is responsible for feedback while the synapse upon the rod bipolar cell is feed‐forward and serves to expand the receptive field of the rod bipolar cell beyond its dendritic field. Alternatively, the latter may contribute to a center‐surround organization of the rod bipolar's receptive field.
Functionally distinct groups of X‐cells in the lateral geniculate nucleus of the cat
Authors: Humphrey Allen L. , Weller Rosalyn E. 
Published: January 2005

AbstractThe latencies and visual response properties of 202 X‐cells in the A‐laminae of the cat dorsal lateral geniculate nucleus (LGN) were examined to investigate the recent claim (Mastronarde, '85,'87a) that functionally different groups of X‐cells reside there. Two groups of X‐cells were found, which differed in their extracellularly recorded responses to spots of light flashed within their receptive fields. One group, constituting one‐third of the sample, responded to spot onset with a profound and often long‐lasting dip in discharge rate, such that cell discharge usually did not reach half maximum until ≥ 100 msec after spot onset. About 70% of these cells also displayed a transient discharge at spot offset. These cells correspond to Mastronarde's lagged X‐cells, and we similarly refer to them as XL‐cells. The second group, constituting the remainder of the X‐cell population, generally responded to spot onset with a short latency (≤ 60 msec) brisk discharge, no detectable XL‐type dip, and a rapid reduction in firing at spot offset. We refer to these neurons as nonlagged (XN) X‐cells; this group probably encompasses all of Mastronarde's non‐XL‐cells.Despite some overlap, the XL‐ and XN‐cells differed in numerous other features. Compared to XN‐cells, XL‐cells exhibited: 1) lower peak rates of discharge and more uniform firing during spot onset; 2) slightly longer latencies and markedly lower probabilities of discharge to optic chiasm stimulation; 3) consistently lower geniculocortical conduction velocities; and 4) markedly lower optimal temporal frequencies when tested with drifting sine wave gratings. No differences were found between the two cell groups in optimal spatial frequency, spatial resolution, or receptive field center size, and there were equal proportions of on‐ and off‐center types of XL‐ and XN‐cells.Analyses of one‐ and two‐dimensional plots of the physiological measures indicate that XL‐ and XN‐cells constitute a physiological continuum. However, the two groups occupy opposite sides of the continuum on many of the measures, with little overlap and with few (< 5%) cells with intermediate properties. Therefore, XL‐cells may be considered a distinct, readily identifiable group.These findings confirm and extend Mastronarde's ('87a) observations on functional differences among geniculate X‐cells. The existence of XL‐cells in the LGN and their apparent absence in the retina (Mastronarde, '87b) add support to the view that the LGN operates as more than a simple relay nucleus, passing on to the cortex in largely unaltered form the signals received from the retina. The differences between XL‐ and XN‐cells suggest that an important transformation occurs in the LGN among XL‐cells, and that it is in the temporal domain rather than in the spatial domain.
Distribution and development of VIP immunoreactive neurons in the spinal cord of the embryonic and newly hatched chick
Authors: Du Fu , Chayvialle Jean‐Alain , Dubois Paul 
Published: January 2005

AbstractThe distribution and development of vasoactive intestinal polypeptide (VIP) immunoreactive elements were studied in the spinal cord of embryonic and newly hatched chicks with the indirect immunofluorescence method. VIP neurons were first detectable in the presumed dorsal horn at stages 27–28 (incubation day 5). Subsequently they increased in number, and by stage 39 (day 12) many occurred in lamina I, in the nucleus of the dorsolateral funiculus, and in the lateral portion of the neck of the dorsal horn throughout the cord. However, at the thoracic level many were also situated lateral to the central canal, with their processes running to the ipsilateral lateral and contralateral ventral funiculi. The pattern described above remained visible in both embryonic and colchicine‐pretreated newly hatched chicks.During development, VIP fibers appeared later than cell bodies. In the gray matter, they were mainly scattered in the intermediate zone, especially around the central canal at all levels examined. In the white matter, however, longitudinal fibers were observed in the lateral funiculus throughout the cord, but mostly at the cervical level, though some also occurred in the ventral funiculus. This finding supports the idea that spinal VIP neurons might project rostrally via the lateral funiculus.In addition, no VIP immunoreactivity was found in the spinal ganglia, but examination of the sympathetic paravertebral ganglia showed immunoreactivity as described by others.
Morphological response of axotomized septal neurons to nerve growth factor
Authors: Gage Fred H. , Armstrong David M. , Williams Lawrence R. , Varon Silvio 
Published: January 2005

AbstractSeptal efferent fibers from, the neurons in the medial septal nucleus are destroyed by fimbria‐fornix aspirative lesion. In the present study we used quantitative morphometric techniques to evaluate the response of these axotomized septal neurons to a constant infusion of nerve growth factor (NGF). By 2 weeks following the lesion, approximately 75% of the cholinergic neurons had degenerated in the untreated rats. The remaining cholinergic neurons showed few signs of the effect of the lesion when stained for a polyclonal antibody to ChAT and examined in 40‐μm‐thick sections. In 1‐μm‐thick sections the remaining ChAT‐immunoreactive (IR) neurons also appeared no different from the intact ChAT neurons. However, non‐ChAT‐IR neurons had a shrunken nucleus, while all other morphometric parameters appeared normal. NGF infusion protected most of the ChAT‐IR neurons from degenerating. The saved neurons had the same parameters as the undamaged ChAT‐IR neurons when examined in either 40‐μm‐ or 1‐μm‐thick sections. In addition, the shrunken appearance of the non‐ChAT‐IR neurons' nuclei was avoided by the NGF infusions.Enlarged ChAT‐IR processes were evident in the dorsolateral quadrant of the septum following damage to the fimbria‐fornix. NGF‐infusions prevented the formation of these processes. Instead, in the treated animals the dorsal lateral quadrant contained a dense plexus of fine ChAT‐IR varicosities.Taken together these results demonstrate that NGF not only can protect the cholinergic neurons from axotomy‐induced degeneration but can also cause the saved neurons to maintain the same morphometric appearance as intact ChAT‐IR neurons. In addition, the lesion‐induced appearance of enlarged ChAT‐IR processes was avoided, and NGF prevents some of the degenerative changes that occur in non‐ChAT‐IR septal neurons after fimbria‐fornix aspiration.