bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evidence that sympathetic preganglionic neurones are arranged in target‐specific columns in the thoracic spinal cord of the rat
Authors: Pyner S. , Coote J. H. 
Published: January 2005

AbstractIt is recognised that selective activation of different target‐specific sympathetic preganglionic neurones forms the basis of many autonomic responses. The anatomical basis for this could be the spatial arrangement of these neurones in the spinal cord nuclei. The present study tested this possibility in the rat by determining the location in single animals of three distinct groups of sympathetic preganglionic neurones, one group projecting to the superior cervical ganglion, another to the stellate ganglion and one to the adrenal medulla. Sympathetic preganglionic neurones to each of these targets were simultaneously labeled with fluorescent dyes, either Fluorogold, Fast Blue, or Diamidino Yellow. The numbers and general morphology of the neurones were similar to previous descriptions, and they were distributed in four subnuclei, the nucleus intermediolateralis pars principalis, the nucleus intermediolateralis pars funiculus, the nucleus intercalatus spinalis, and the nucleus intercalatus spinalis pars paraependymalis. It was shown that all three groups of neurones were represented in the more medial sympathetic nuclei, but in the nuclei at the lateral border of the intermediate grey matter each one of the three groups of neurones occupied a discrete location. Adrenal medullary sympathetic preganglionic neurones occupied a lateral aspect, the superior cervical ganglion sympathetic preganglionic neurones a medial aspect, and the stellate ganglion sympathetic preganglionic neurones a space between. Some sympathetic preganglionic neurones were double labeled after dye injections into the superior cervical and stellate ganglion thus indicating that they projected to both ganglia. It is concluded that there are populations of sympathetic preganglionic neurones arranged in horizontal columns which only send axonal projections to the superior cervical, stellate ganglia, or adrenal medulla, respectively, and hence are target specified for each structure. This arrangement is likely to be of importance in understanding selective activation of autonomic effectors, a feature of different types of behaviour. © 1994 Wiley‐Liss, Inc.
Topographical distribution of reduced nicotinamide adenine dinucleotide phosphate‐diaphorase in the brain of the Japanese quail
Authors: Panzica G. C. , Arévalo R. , Sánchez F. , Alonso J. R. , Aste N. , Viglietti‐Panzica C. , Aijón J. , Vázquez R. 
Published: January 2005

AbstractThe distribution of reduced nicotinamide adenine dinucleotide phosphate (NADPH)‐diaphorase activity was histochemically investigated in the Japanese quail brain. This enzyme is now considered responsible for the synthesis of nitric oxide, a novel neural messenger whose distribution has not been described in the avian brain until now. The histochemical technique provides a simple and reliable method for staining selected populations of neurons throughout the avian brain. In the telencephalon several regions showed heavily stained NADPH‐diaphorase positive neurons and processes. In particular the paleostriatal‐paraolfactory lobe complex showed the greatest presence of both positive cells and processes. Neurons and processes were also observed in several regions of the hyperstriatum as well as in the archistriatal nucleus taeniae. Some regions, such as the ectostriatum and the hippocampus, had no positive elements. In the diencephalon, the magnocellular hypothalamic system, which in mammals shows NADPH‐diaphorase activity, did not show any particular accumulation of reaction product. On the contrary, retinorecipient areas, such as the visual suprachiasmatic nucleus and the lateral geniculate complex, displayed a composite structure of both positive neurons and processes. The brainstem revealed a large NADPH‐diaphorase positive population extending through the tegmental nuclei to the locus coeruleus and subcoeruleus. A complex organization was also observed in the optic lobe, where fusiform elements were distributed within the stratum griseum and superficialis of the tectum. In the medulla, a dense terminal field was observed at the level of the nucleus of the solitary tract, whereas scattered neurons were located within the reticular nuclei. Although the staining of neurons and tracts was highly selective, the positive cells did not correspond to any single known neurotransmitter, neuropeptide, or neuroactive molecule system. Several sensory pathways were heavily stained for the NADPH‐diaphorase, including part of the olfactory, visual, and auditory pathways. The findings of the present study reveal that the NADPH‐diaphorase‐containing systems in the avian brain are organized according to a pattern comparable, because of its complexity, to that observed in mammals. However, important interspecific differences suggest that this novel neural system might be involved in diverse tasks. © 1994 Wiley‐Liss, Inc.
Antibody to neural cell adhesion molecule can disrupt the migration of luteinizing hormone‐releasing hormone neurons into the mouse brain
Authors: Schwanzel‐Fukuda M. , Reinhard G. R. , Abraham S. , Crossin K. L. , Edelman G. M. , Pfaff D. W. 
Published: January 2005

AbstractThe neurons which synthesize and release luteinizing hormone‐releasing hormone (LHRH), are hypothesized to originate in the epithelium of the medial olfactory pit and to migrate into the brain along a scaffolding made up of neural cell adhesion molecule (NCAM)‐immunoreactive branches of the terminal and vomeronasal nerves. These LHRH neurons, studied by immunocytochemical and autoradiographic procedures, were found to originate within a very short period of embryogenesis, specifically day 10, in mice, and to follow a remarkably ordered spatiotemporal course along the migration route into the brain.The purpose of the present experiments was to determine whether perturbation of the NCAM‐immunoreactive migration route, at a particular time in development, would arrest the migration of LHRH neurons into the brain. We found that a 1 μl injection of antiserum to NCAM into the area of the olfactory pit, on day 10 of embryogenesis, significantly reduced the number of LHRH‐immunoreactive neurons seen in the epithelium of the medial olfactory pit, with a concomitant significant reduction in the number of LHRH‐immunoreactive cells seen outside of the placode, on the migration route. These results confirm our initial hypothesis that LHRH neurons migrate from the epithelium of the olfactory pit to the brain and indicate that NCAM plays a causal role in this phenomenon. © 1994 Wiley‐Liss, Inc.
Persistence of rubrospinal projections following spinal cord injury in the rat
Authors: Theriault Elizabeth , Tator Charles H. 
Published: January 2005

AbstractRecent neurophysiological and magnetic resonance imaging studies of clinically “complete” human spinal cord injuries indicate that some patients have considerable subclinical function and substantial morphological integrity of descending spinal tracts. In contrast, extensive histopathological changes, including cell death, have been described in central nervous system nuclei projecting to the cord following experimental transection or hemisection of the spinal cord in animal models. We have used a rodent model of severe compression cord injury that more closely resembles the clinical pathophysiology to investigate the extent of the persistence of the rubrospinal projection. Counts of red nucleus neurons retrogradely labelled with Fluorogold demonstrate that in contrast to the results obtained with transection models, compression injuries of the spinal cord donotresult in massive loss of rubrospinal projections, at least up to 8 weeks postinjury. The results also suggest that many of the axons persist distal to the lesion site and that they are functionally intact with respect to retrograde transport capabilities. © 1994 Wiley‐Liss, Inc.
Reduced cortical inhibitory synaptogenesis in organotypic cerebellar cultures developing in the absence of neuronal activity
Authors: Seil Fredrick J. , Drake‐Baumann Rosemarie 
Published: January 2005

AbstractOrganotypic cerebellar cultures derived from newborn mice were continuously exposed to medium containing tetrodotoxin and elevated levels of magnesium to block all electrical activity. After 2 weeks in vitro, no activity was evident during the first 15–20 minutes following transfer to a recording medium without blocking agents. Thereafter, cortical discharge rates increased until a state of sustained hyperactivity was reached. Ultrastructural examination of such cultures revealed a reduction of inhibitory Purkinje cell somatic synapses to half the control value along with an even greater reduction of axodendritic synapses (largely inhibitory) in the cortical neuropil. No loss of axospinous synapses (excitatory) was evident. These results support the concept that spontaneous neuronal activity is necessary for the full development of inhibitory circuitry. © 1994 Wiley‐Liss, Inc.
Undernutrition of rats during early life does not affect the total number of cortical neurons
Authors: Bedi K. S. 
Published: January 2005

AbstractUndernutrition during early life is known to cause deficits and distortions in brain structure. However, it remains uncertain whether this includes a diminution of the total numbers of neurons. Recent advances in stereological techniques have made it possible to obtain unbiased estimates of total numbers of cells in well‐defined biological structures. Rats were undernourished from day 16 of gestation to 30 postnatal days of age by standardized procedures. These rats and well‐fed control rats were anaesthetized and killed by intracardiac perfusion with fixatives at 70 days of age. The left cerebral hemisphere from each animal was embedded in Paraplast and serially sectioned. The sections were analyzed via the Cavalieri principle to obtain the total cortical volume and by the “disector” method to estimate the numerical density of neurons in the cortex. These values were later used to compute estimates of the total number of cortical neurons for each animal. Well‐fed control rats had 26.9 million cortical neurons, while the previously undernourished animals had 24.8 million. The difference between these two groups was not statistically significant. It therefore appears that undernutrition of rats during early postnatal life does not affect the total numbers of neurons in the cerebral cortex. © 1994 Wiley‐Liss, Inc.
Light and electron microscopic studies of the effects of p‐chloroamphetamine on the monoaminergic innervation of the rat spinal cord
Authors: Ridet Jean‐Luc , Geffard Michel , Privat Alain 
Published: January 2005

AbstractA previous report has shown that small diameter serotoninergic (5‐HT) axons innervating the forebrain are selectively eliminated by treatment with an amphetamine derivative, (±)p‐chloroamphetamine (PCA; Mamounas et al., [1991] J. Comp. Neurol. 314:558—586). It is well known that the spinal cord is the target of numerous monoaminergic fibers of different types. We have previously shown that the dorsal and ventral horns and the intermediolateral cell column are innervated by numerous serotonin‐, noradrenaline‐ and dopamine‐containing axons, including both thin axons with small varicosities and beaded axons with large varicosities. In all these regions, the large majority of fine indolaminergic fibers do not establish synaptic contacts, contrasting with the beaded axons which mostly exhibit synapses. The present work was conducted to study the effect of PCA on the monoaminergic innervation of the adult rat spinal cord. Animals received two subcutaneous doses of PCA 24 hours apart and were perfused 3 weeks later. Immunocytochemistry was performed to detect 5‐HT, noradrenergic and dopaminergic fibers by using light and electron microscopy. Light microscopy revealed that PCA treatment caused a marked and selective elimination of the fine 5‐HT‐immunoreactive fibers, mainly found in the dorsal horn, but spared all other larger axons. This selective effect on the dorsal horn innervating thin 5‐HT fibers was confirmed with the electron microscope by calculating the synaptic incidence(s) of monoaminergic innervation. These results suggest that fine and beaded 5‐HT axons correspond to two anatomically, biochemistry and pharmacologically different types of fibers, which could arise from two subpopulations of brainstem neurons.In addition, this drug could be used to provide an experimental animal, devoid of 5‐HT nonsynaptic fibers, thereby facilitating a study on the role of dorsal horn nonsynaptic system in pain modulation. © 1994 Wiley‐Liss, Inc.
Neuroanatomy of the rhabdocoel flatworm Mesostoma ehrenbergii (focke, 1836). I. Neuronal diversity in the brain
Authors: Elvin Mark , Koopowitz Harold 
Published: January 2005

AbstractWe investigated the neuronal configurations of brain cells in the rhabdocoel flatworm Mesostoma ehrenbergiiand compared them to those of the polyclad Notoplan acticolato determine neuronal synapomorphies for these different flatworm clades. The fluorescent dye Lucifer yellow was used to fill and visualize cells in the brain of M.ehrenbergii. The predominant cell types for both animals were heteropolar bipolar and heteropolar multipolar cells. Isopolar bipolar and isopolar multipolar cells wer also found but in much lower numbers. Small amacrine‐type multipolar cells tht might be glial in nature were also found in an area of neuropil. A few unipolar cells were found that ranged from small amacrine‐type cells to typical invertebrate‐type unipolars. In addition, a number of morphologically identified cells found in different animals are described. © 1994 Wiley‐Liss, Inc.
Distribution and proportions of GABA‐Immunoreactive neurons in cat primary somatosensory cortex
Authors: Li Jianying , Schwark Harris D. 
Published: January 2005

AbstractCertain receptive field properties of cortical neurons depend upon inhibitory, GABAergic inputs. In the somatosensory cortex, iontophoresis of bicuculline, a GABAA receptor blocker, results in enlargement of receptive fields. However, bicuculline's effectiveness in changing receptive field size varies with the neuron's adaptation characteristics, location within a particular submodality region, and laminar location. To test whether regional differences in the effectiveness of bicuculline are correlated with the distribution of cortical GABAergic neurons, we determined the number and proportion of GABA‐immunoreactive [GABA(+)] neuron, within cat primary somatosensory cortex. The laminar distribution of GABA(+) neurons was similar across all four cytoarchitechonic areas of primary somatosensory cortex, with layer II containing the highest areal density of GABA(+) neurons. Numerical proportions of GABA(+) neurons in the total neuron population were similar in areas 3b and 2 (29.8% and 22.6%, respectively). Laminar distributions of the proportions of GABA(+) neurons were also similar in these two areas; in both areas layer I contained the highest proportion of GABA(+) neurons. The laminar distribution of GABA(+) neuron density as well as GABA(+) neuron proportion differed from the reported laminar distribution of bicuculline effects on respective field size. Moreover, within area 3b, these measures showed no evident pattern that might correspond to rapidly adaptation and slowly adapting submodality regions. © 1994 Wiley‐Liss, Inc.
Horizontal cells and cone photoreceptors in human retina: A Golgi‐electron microscopic study of spectral connectivity
Authors: Ahnelt Peter , Kolb Helga 
Published: January 2005

AbstractConnections of the three human horizontal cell (HC) types with overlying cone pedicles have been studied via electron microscopy (EM). Because blue cones (B‐cones) can be recognized on distinctive morphological criteria, we could determine their presence by light microscopy (LM) in the mosaic overlying HC dendritic trees. Then we could confirm the presence or absence of dendritic contacts to B‐cone pedicles by examining EM serial sections and making reconstructions of examples of the three HC types.Three HI cells have been reconstructed. Their dendritic terminals ended as lateral elements of ribbon synapses in green and red cone pedicles (G‐ and R‐cones) primarily. B‐cones pedicles in HI cell dendritic fields received no more than one or two contacts. Six reconstructed HII cells were found to contact all the pedicles within their dendritic field. However, their dendritic reached especially for B‐cones pedicles and innervated them with disproportionately large number of terminals compared with G‐ and R‐cines. HII axons appeared to contact B‐cones exclusively. The four reconstructed HIII cells were found to avoid completely B‐cones in their dendritic fields.Data have been collected on synaptic ribbon lengths at HII and HIII lateral elements in the B‐cone as compared with G‐ and R‐cone pedicles. HIII dendritic terminals end almost exclusively at the smaller ribbons and HI dendrites at the large ribbons. The number of dendritic terminals provided by the HCs to G‐and R‐cone pedicles as compared B‐cone pedicles has been more accurately quantitated than was possible in the LM analysis (accompanying paper).New findings on the morphology of B‐cone pedicles in peripheral retina have revealed that 1) B‐cone pedicles end further vitread in the outer plexiform layer (OPL) than other cone pedicles, thereby forming a sublayer of the OPL neuropil, here named OPLb, in comparison to OPLa, where the G‐ and R‐cone pedicles end; 2) B‐cone pedicles have very few telodentrial connections; and 3) in peripheral retina (probably beyond 8 mm from the fovea to the ora serrata), they are bi‐ or trilobed, with each lobe containing separate synaptic invaginations. The vitread position and unique morphology of B‐cone pedicles appear to relate directly to the unique morphology and unusual connectivity patterns of both their B‐cone‐specific bipolar and B‐cone‐related horizontal cell, the HII cell. Taken together with the LM and quantitative data of our two preceding papers, these findings provide morphological evidence that a chromatically selective weighting pattern in HCs and could play a role in color‐opponent surround formation in the human retina. © 1994 Wiley‐Liss, Inc.
Pedunculopontine nucleus in the squirrel monkey: Distribution of cholinergic and monoaminergic neurons in the mesopontine tegmentum with evidence for the presence of glutamate in cholinergic neurons
Authors: Lavoie Brigitte , Parent André 
Published: January 2005

AbstractThe topographical relationships between cholinergic neurons, identified by their immuno‐reactivity for choline acetyltransferase (ChAT) or their staining for β‐nicotinamide ademine dinucleotide phosphate (NADPH)‐diaphorase, and dopaminergic, serotoninergic, Nonadrenergic, and glutamatergic neurons that occur in the mesopontine tegmentum, were studied in the squirrel monkey (Saimiri sciureus). The ChAT‐positive neurons in the pedunculopontine nucleus (PPN) form two distinct subpopulations, one that corresponds to PPN pars compacta(PPNc) and the other to PPN pars dissipata (PPNd). The ChAT‐positive neurons in PPNc are clustered along the dorsolateral border of the superior cerebellar peduncle (SP) at trochlear nucleus levels, whereas those in PPNd are scattered along the SP from midmesencephalic to midpontine levels. At levels caudal toe the trochlear nucleus, ChAT‐positive neurons corresponding to the laterodorsal tegmental nucleus (LDT) lie within the periaqueductal gray and extend caudally as far as locus coeruleus levels. All ChAT‐positive neurons in PPN and LDT stain for NADPH‐diaphorase; the majority of large neurons in PPN and LDT are cholinergic, but some large neurons devoid of NADPH‐diaphorase also occurnin these nuclei. Cholinergic neurons in the mesopontine tegmentum form clusters that are largely segregated from raphe serotonin immunoreactive neurons, as well as from nigral dopaminergic and coeruleal noradrenergic neurons, as revealed by tyrosine hydroxylase immunohistochemistry. Nevertheless, dendrites of cholinergic and noradrenergic neurons are clolinergic and noradrenergic neurons are closely intermingled, suggesting the possibility of dendrodendritic contacts. In addition, numerous large and medium‐sized glutamate‐immunoreactive neurons are intermingled among cholinergic neurons in PPN. Furthermore, at trochlear nucleus levels, about 40% of cholinergic neurons display glutamate immunoreactivity, whereas other neurons express glutamate or ChAT immunoreactivity only. This study demonstrates that (1) cholinergic neurons remain largely segregated from monoaminergic neurons throughout the mesopontine tegmentum and (2) PPN contains cholinergic and glutamatergic neurons as well as neurons coexpressing ChAT and Glutamate in primates. © 1994 Wiley‐Liss, Inc.
Development of specificity in corticospinal connections by axon collaterals branching selectively into appropriate spinal targets
Authors: Kuang Rong Zhen , Kalil Katherine 
Published: January 2005

AbstractCorticospinal projections in adult rodents arise exlusively from layer V neurons in the sensorimotor cortex. These neurons are topographically organized in their connections to spinal cord targets. Previous studies in rodents have shown that the mature distribution pattern of corticospinal neurons develops during the first 2 weeks postnatal from an initial widespread pattern that includes the visual cortex to a distribution restricted to the sensorimotor cortex. To determine whether specificity in corticospinal connections also emerges from an intially diffuse set of projections, we have studied the outgrowth of corticospinal axons and the formation of terminal arbors in developing hamsters. The sensitive fluorescent tracer 1, 1′, dioctadecyl‐3, 3, 3′, 3′‐tetramethylindocarbocyanine perchlorat (DiI) was used to label corticospinal axons from the visual cortex or from small regions of the forelimb or hindlimb sensorimotor cortex in living animals at 4–17 days postnatal. Initially axon outgrowth was imprecise. Some visual cortical axons extended transiently beyond their permanent targets in the pontine nuclei, by growing through the pyramidal decussation and in some cases extending as far caudally as the lumbar enlargement. Forelimb sensorimotor axons also extended past their targets in the cervical enlargement, in many cases growing in the corticospinal tract to lumbar levels of the cord. By about 17 days postnatal these misdirected axons or axon segments were withdrawn from the tract. Despite these errors in axon trajectories within the corticospinal tract, terminal arbors branching into targets in the spinal gray matter were topographically appropriate from the earliest stages of innervation. Thus visula cortical axons never formed connections in the spinal cord, forelimb sensorimotor axons arborized only in the cervical enlargement, and hindlimb cortical axons terminated only in the lumbar cord at all stages of development examined. Corticospinal arbors formed from collaterals that extended at right angles from the shafts of primary axons, most likely by the process of interstitial branching after the primary growth cone had extended past the target. Once collaterals extended into the spinal gray matter, highly branched terminal arbors formed within 2–4 days, beginning at about 4 and 8 days postnatal for the cervical and lumbar enlargements, respectively. These results show that specificity in connectivity is achieved by selectivty growth of axon collaterals in to appropriate spinal targets from the beginning and not by the later remodeling of intially diffuse connections. In contrast, errors occur in the initial outgrowth of axons in the corticospinal tract, which are subsequently corrected. Copyright © 1994 Wiley‐Liss, Inc.