bluuebunny/crossref_metadata_2025_split huggingface dataset:
Noradrenergic innervation of monkey prefrontal cortex: A dopamine‐β‐hydroxylase immunohistochemical study
Authors: Lewis David A. , Morrison John H. 
Published: January 2005

AbstractNorepinephrine has been implicated in the regulation of a number of cortical functions, yet relatively little is known about the anatomical organization of noradrenergic axons in the expanded and highly differentiated prefrontal cortex of primates. In this study, the distribution of fibers containing dopamine‐ß‐hydroxylase (DBH), the enzyme that converts dopamine to norepinephrine, was characterized immunohistochemically in the prefrontal cortical regions of Old World cynomolgus monkeys (Macaca fascicularis) and New World squirrel monkeys (Saimiri sciureus). In both species, differences in the density of DBH‐labeled fibers were detected both across and within many prefrontal cytoarchitectonic regions. In cynomolgus monkeys, area 8B had the greatest density of DBH‐immunoreactive fibers; within this region, the medial surface had a greater density of labeled processes than the dorsal surface. Areas 9 and 24 also had a high density of DBH‐labeled fibers, areas 11, 12, 13 and 25 were of intermediate density, and portions of areas 10 and 46 had the lowest density of immunoreactive fibers. Regional differences in the density of DBH‐immunoreactive fibers were also present in squirrel monkey prefrontal cortex.Despite the regional variations in the density of DBH‐immunoreactive fibers, the laminar distribution of these fibers was very similar across cytoarchitectonic areas of cynomolgus prefrontal cortex. Layer I contained a low density of labeled fibers which were primarily tangential in orientation. The predominantly radially oriented fibers in layers II‐IV were slightly higher in density. The density of both radially and tangentially oriented immunoreactive fibers increased substantially in layer V. Fiber density decreased in layer VI; a band of tangentially oriented fibers was present in the deep portion of this layer. With a few exceptions, the laminar distribution of DBH‐immunoreactive fibers in the prefrontal regions of squirrel monkey cortex was similar to that of cynomolgus monkey.Since other data suggest that anti‐DBH selectively labels noradrenergic axons in monkey neocortex, the distinctive innervation patterns exhibited by DBH‐immunoreactive fibers reveal the regions and layers that may be the principal sites of action of norepinephrine in exerting its effects on prefrontal cortical function.
Extension of the critical period for developmental plasticity of the corticospinal pathway
Authors: Bregman Barbara S. , Kunkel‐Bagden Ellen , McAtee Marietta , O'Neill Andrea 
Published: January 2005

AbstractThe corticospinal tract (CST) of the rat undergoes a prolonged period of postnatal development. Lesions of the presumptive CST pathway at birth are followed by the aberrant rerouting of the developing corticospinal axons around the lesion site through adjacent undamaged CNS tissue. This developmental plasticity becomes severely restricted by 5‐6 days of age, so the axons are no longer capable of growth around the site of injury. The aim of the current study was to determine whether altering the environment at the site of injury by filling the lesion with transplanted fetal spinal cord tissue could prolong the critical period for developmental plasticity of the corticospinal pathway. The spinal cord was damaged (overhemisection) at three stages in the development of the corticospinal (CS) pathway: 1) prior to the arrival of CS axons, 2) after the axons elongated through the cord but prior to synaptogenesis, and 3) after both axonal elongation and synaptogenesis were completed. One to 9 months later, anterograde neuronal tracing with horseradish peroxidase was used to assess the growth of the corticospinal pathway with or without a fetal transplant at the site of injury, and the pattern of labeling was compared with that observed in adult nonlesioned control animals. Our results indicate that the presence of a transplant prolongs the critical period for developmental plasticity of the CST. Transplants elicited growth of CST axons throughout the postnatal period examined. CST axons damaged prior to synaptogenesis exhibited more robust growth than those lesioned after synaptogenesis had been completed. These results suggest that both environmental and neuronal factors interact to regulate the response of immature CS neurons to injury.
Neurogenesis and cell death in the isthmic nuclei of the frog Limnodynastes dorsalis
Authors: Dann J. F. , Beazley L. D. 
Published: January 2005

AbstractIn Limnodynastes dorsalis, neurogenesis of the isthmic nuclei was determined by 3H‐thymidine autoradiography. The nuclei developed in a rostroventral to caudodorsal direction. Peak neurogenesis occurred in midlarval life, resulting in the formation of a substantial protion of each nucleus. Cell death was evidenced by the presence of pyknotic cells within the nucleus in all except the earliest stages. Peak cell death occurred around metamorphic climax. It was during this period that a rim neuropil appeared that segregates within the nucleus the contralateral and ipsilateral components of the tecto‐isthmo‐tectal pathways underlying binocular vision. It is also a time just prior to the onset of electrophysiologically detectable ipsilateral visual responses. However, no systematic cell death was found. Therefore the role of cell death in the formation of the isthmic nuclei remains obscure, although it may be involved in the establishment of tecto‐isthmo‐tectal connections.
Morphology and distribution of synapses onto a type of large field ganglion cell in the retina of the goldfish
Authors: Hitchcock Peter F. 
Published: January 2005

AbstractThe morphology and dendritic distribution of terminals that synapse onto a type of large‐field ganglion cell in the retina of the goldfish are described. Electron microscopy was combined with retrograde labelling of cells with horseradish peroxidase (HRP). Synapses from both amacrine (four types) and bipolar cells contacted the dendrites (all orders) of these cells. In contrast to a recent report describing the synaptic organization of large‐field ganglion cells in the catfish (Sakai et al., '86), the synapses were relatively evenly distributed throughout the dendritic arbor, not clustered at discrete sites, and no presynaptic specializations were seen in the dendrites of the ganglion cells.
Morphology and physiology of cells in slice preparations of the dorsal cochlear nucleus of mice
Authors: Oertel Donata , Wu Shu Hui 
Published: January 2005

AbstractHorseradish peroxidase (HRP) was injected into cells from which intracellular recordings were made in slices of the dorsal cochlear nucleus (DCN) in order to correlate physiology with morphology. In general, the morphology of cells labeled intracellularly with HRP corresponded to those made with Golgi impregnations in mice and other mammals. The following cells were labeled: one granule cell, four cartwheel cells, eight fusiform cells, two other cells in the fusiform cell layer, and two tuberculoventral association cells in the deep layers of the DCN The axon of the granule cell runs parallel to isofrequency laminae with collaterals branching perpendicularly and running along the tonotopic axis. The cartwheel cells have dendrites in the molecular layer that are densely covered with spines. The axon of one cell terminates just dorsally to the cell body. Fusiform cells have the characteristic spiny, apical and smooth, basal dendrites. The basal dendrites are conspicuously oriented parallel to isofrequency laminae. Axons of the fusiform cells exit through the dorsal acoustic stria without branching. The two tuberculoventral association cells in the deep DCN have axons that terminate both in the deep DCN, within the same isofrequency lamina that contains the cell body, and in the ventral cochlear nucleus (VCN).Intracellular recordings from 11 of these cells show that they cannot be distinguished on the basis of their responses to intracellularly injected current. All cell types fired large action potentials that were followed by a fast and a slower undershoot, distinguishing them from cells of the VCN but not from one another. Most cells responded to shocks of the auditory nerve root with early EPSPs and later IPSPs. The latencies of EPSPs show that some were monosynaptic and others polysynaptic. That there was no systematic relationship between the latencies of EPSPs and the cell types from which they were recorded shows that shocks to the nerve root may have activated more than just the large, myelinated, auditory nerve fibers.
Distribution of sympathetic preganglionic neurons and monoaminergic nerve terminals in the spinal cord of the rat
Authors: Anderson C. R. , McLachlan Elspeth M. , Srb‐Christie Olga 
Published: January 2005

AbstractA study was made of the distribution of sympathetic preganglionic neurons identified by retrograde labeling with horseradish peroxidase from various peripheral nerve trunks and of the distributions of monoaminergic terminals in the spinal cord of the rat. Nerve terminals were stained immunohistochemically by using antisera raised against tyrosine hydroxylase, phenylethanolamine‐N‐methyl‐transferase, neuropeptide Y, and 5‐hydroxytryptamine and by using formaldehyde‐induced fluorescence. The three‐dimensional distribution of sympathetic preganglionic neurons was described by using computer reconstruction and compared with the arrangement of each population of immunohistochemically stained terminals in the intermediate zone. Although monoaminergic terminals are associated with most sympathetic neurons, particularly in the intermediolateral column, the relationship of many terminals to sympathetic neuron somata in other parts of the intermediate zone is tenuous. Some of the descending innervation may terminate on interneurons. The data are consistent with the coexistence of phenylethanolamine‐N‐methyl‐transferase and neuropeptide Y in terminals arising from cell bodies in the C1 region in the ventrolateral medulla and with the presence of at least two populations of catecholaminergic terminals as well as the adrenergic one. Serotoninergic terminals are denser and have a different arrangement from those of catecholaminergic terminals in the intermediate zone.
Rapid changes in cochlear nucleus cell size following blockade of auditory nerve electrical activity in gerbils
Authors: Pasic Thomas R. , Rubel Edwin W. 
Published: January 2005

AbstractLarge spherical cells of the mammalian anteroventral cochlear nucleus (AVCN) receive direct excitatory input from auditory nerve axons. Trans‐synaptic regulation of neuronal cell size and cell number after cochlear ablation has been previously demonstrated in neonates of several vertebrate species, including the gerbil. Such changes may be related to loss of spontaneous or evoked auditory nerve electrical activity or to loss of activity‐independent factors. We have developed a method to chronically, yet reversibly, block auditory nerve electrical activity without violating the integrity of the inner ear. Tetrodotoxin (TTX) was embedded in an ethylene‐vinyl acetate copolymer resin (Elvax). A small piece of Elvax containing TTX was placed next to the round window membrane, which allowed TTX to diffuse into the inner ear. As a measure of the effectiveness of manipulation, the onset, duration, and magnitude of the auditory threshold shift were measured by the auditory brainstem response. The sound‐evoked response was abolished within 10 minutes of placement of TTX on the round window membrane. The duration of threshold shift was dose‐dependent and lasted 24–46 hours. Implants of Elvax without TTX did not produce a significant threshold shift. TTX, which blocks voltage‐gated sodium channels, did not abolish the potassium‐based cochlear microphonic response.The consequence of blocking afferent electrical activity on gerbil AVCN large spherical cells was examined by measuring their cross‐sectional area after each of four manipulations: unilateral auditory nerve action potential blockade with TTX; unilateral surgical cochlear ablation; ipsilateral TTX exposure/contralateral cochlear ablation; and unilateral sham operation (Elvax without TTX). Large spherical cells ipsilateral to cochlea TTX exposure were 21% smaller than contralateral large spherical cells. Cells ipsilateral to cochlear ablation were 25% smaller than contralateral cells. There was not a significant difference between the effect of cochlear ablation and TTX exposure on AVCN cell size and there was not a reliable effect of sham operation. These findings are consistent with previous work in the avian auditory system and support the hypothesis that electrical activity or the sequelae of electrical activity is a major factor in transneuronal regulation of cell size.
Changes in dorsal horn synaptic disc numbers following unilateral dorsal rhizotomy
Authors: Chung K. , McNeill D. L. , Hulsebosch C. E. , Coggeshall R. E. 
Published: January 2005

AbstractThe present study estimates the numbers of synaptic discs and numbers of degenerating synaptic terminals in laminae I–IV of the rat S2 dorsal horn ipsi‐ and contralateral to unilateral dorsal rhizotomy. These data allow us to estimate the loss of synapses of primary afferents and to correlate this loss with the rate of axon disappearance in the proximal stump of a transected S2 dorsal root. Our first findings are that 47% of the ipsilateral synapses and 27% of the contralateral synapses disappear within a day following unilateral rhizotomy. Conclusions are that the predominant synaptic population in this part of the rat spinal cord is of primary afferent origin and that there is an extensive bilateral projection of the dorsal root fibers. The contralateral projection is confirmed by the appearance of numerous degenerating terminals on the contralateral side. We also find that synaptic loss and appearance of degenerating terminals occur relatively synchronously in laminae I–IV. Finally we find that the time course of the synaptic loss correlates primarily with the disappearance of unmyelinated fibers in the proximal stump of the transected dorsal root.
Human reticular formation: Cholinergic neurons of the pedunculopontine and laterodorsal tegmental nuclei and some cytochemical comparisons to forebrain cholinergic neurons
Authors: Mesulam M. ‐Marsel , Geula Changiz , Bothwell Mark A. , Hersh Louis B. 
Published: January 2005

AbstractCholine acetyltransferase immunohistochemistry showed that the human rostra1 brainstem contained cholinergic neurons in the oculomotor, trochlear, and parabigeminal nuclei as well as within the reticular formation. The cholinergic neurons of the reticular formation were the most numerous and formed two intersecting constellations. One of these, designated Ch5, reached its peak density within the compact pedunculopontine nucleus but also extended into the regions through which the superior cerebellar peduncle and central tegmental tract course. The second constellation, designated Ch6, was centered around the laterodorsal tegmental nucleus and spread into the central gray and medial longitudinal fasciculus. There was considerable transmitterrelated heterogeneity within the regions containing Ch5 and Ch6. In particular, Ch6 neurons were intermingled with catecholaminergic neurons belonging to the locus coeruleus complex. The lack of confinement within specifiable cytoarchitectonic boundaries and the transmitter heterogeneity justified the transmitter‐specific Ch5 and Ch6 nomenclature for these two groups of cholinergic neurons.The cholinergic neurons in the nucleus basalis (Ch4) and those of the Ch5‐Ch6 complex were both characterized by perikaryal heteromorphism and isodendritic arborizations. In addition to choline acetyltransferase, the cell bodies in both complexes also had high levels of acetylcholinesterase activity and nonphosphorylated neurofilament protein. However, there were also marked differences in cytochemical signature. For example, the Ch5‐Ch6 neurons had high levels of NADPHd activity, whereas Ch4 neurons did not. On the other hand, the Ch4 neurons had high levels of NGF receptor protein, whereas those of Ch5‐Ch6 did not.On the basis of animal experiments, it can he assumed that the Ch5 and Ch6 neurons provide the major cholinergic innervation of the human thalamus and that they participate in the neural circuitry of the reticular activating, limbic, and perhaps also extrapyramidal systems.
Axonal branching of the olivocerebellar projection in the rat: A double‐labeling study
Authors: Hrycyshyn A. W. , Ghazi H. , Flumerfelt B. A. 
Published: January 2005

AbstractCollateralization of olivocerebellar (climbing) fibers was studied in the rat by means of the fluorochrome double‐labeling technique. Most of the olivocerebellar projection is crossed except for a minimal ipsilateral component which arises from the most rostral part of the inferior olivary nucleus (ION). ION neurons in the caudolateral part of the medial accessory olive (MAO) and the dorsal accessory olive (DAO) give off axons that branch to supply both hindlimb areas of the contralateral cerebellar cortex, i.e., the rostral anterior lobe and the caudal paramedian lobule. In addition, neurons in the middle one‐third of the contralateral MAO and DAO send axons that divide to terminate in both the caudal part of the anterior lobe and the rostral part of the paramedian lobule (forelimb receiving areas). Neurons within the caudal part of the MAO, the lateral part of the DAO, the ventral lamella of the principal olive (PO), and the dorsomedial cell column (DMCC) send axonal branches that terminate within at least two different areas of the same sagittal zones throughout the contralateral cerebellar cortex. Thus, the ION contains specialized cells that provide a divergence of integrated information from the ION to at least two cerebellar regions.
HRP labeling and ultrastructural localization of prepacemaker terminals within the medullary pacemaker nucleus of the weakly electric gymnotiform fish Apteronotus leptorhynchus
Authors: Szabo T. , Heiligenberg W. , Ravaille‐Veron M. 
Published: January 2005

AbstractThe prepacemaker nucleus (PPN) in the midbrain of gymnotiform electric fish projects to the pacemaker nucleus (PN) in the medulla and modulates its rhythmic discharges in the context of social electric communication. Anterograde labeling of PPN axons with HRP and ultrastructural studies of their terminations in the PN have shown that PPN neurons form synaptic contacts with both types of neurons in the PN, pacemaker cells, and relay cells.
Retrovesicular ganglion of the nematode Ascaris
Authors: Angstadt James D. , Donmoyer Judith E. , Stretton Antony O.W. 
Published: January 2005

AbstractThe nematode nervous system is distinguished by the small number and morphological simplicity of its neurons. Recently, the shapes and synaptic interactions of each of the 302 neurons in the small free‐living nematode, Caenorhabditis elegans, have been determined from reconstructions of serial sections by electron microscopy. Comparable anatomical studies of the large parasitic nematode Ascaris have concentrated on the dorsal and ventral nerve cords where reconstructions of motor neurons by light microscopy led to the identification of seven distinct types of motor neurons, each corresponding to a homologous cell type in C. elegans.In this study the shapes of the 13 neurons with cell bodies in the retrovesicular ganglion (RVG) of Ascaris suum were reconstructed from light micrographs of serial sections. In other preparations the morphology of RVG neurons was observed in whole mounts after the cells were impaled with microelectrodes and injected with the fluorescent dye Lucifer yellow. The intracellular electrodes also permitted electrical recordings and revealed that one type of cell, the AVF‐like interneuron, expresses spontaneous repetitive plateau potentials.Comparisons of neuronal morphologies in the retrovesicular ganglia of Ascaris and C. elegans suggest that each neuron in Ascaris can be assigned a corresponding homolog in C. elegans. These data provide further evidence for a remarkable conservation of neuronal morphology in nematodes despite large differences in size and habitat.
Nonspiking interneurons in the ventilatory central pattern generator of the shore crab, Carcinus maenas
Authors: Dicaprio R. A. 
Published: January 2005

AbstractEight nonspiking interneurons were identified that are elements of the central pattern generator controlling ventilation in the shore crab, Carcinus maenas. Intracellular recordings from these neurons in an isolated ganglion preparation revealed that these cells exhibit large amplitude oscillations in their membrane potentials, which are in‐phase with the ventilatory motor pattern. These oscillations are present during the expression of the two distinct ventilatory motor output patterns corresponding to forward and reversed ventilation, and the oscillations stopped during pauses in the ventilatory rhythm. Injection of intracellular current pulses into these interneurons caused a resetting of the ongoing ventilatory rhythm, indicating that these cells are part of the ventilatory central pattern generator. The structure of each interneuron was determined by the intracellular injection of Lucifer Yellow dye. These neurons have a large diameter main neurite ranging from 10 to 20 μm in diameter with very restricted primary and secondary branching from the main neurite. All of the interneurons are restricted to a single hemiganglion and perturbation of these cells with intracellular current pulses only affect the motor output of the hemiganglion containing the interneuron. These eight nonspiking interneurons appear to be the primary components of the central pattern generator underlying ventilation in the crab.
Distribution and morphometric characteristics of oxytocin‐ and vasopressin‐immunoreactive neurons in the rabbit hypothalamus
Authors: Schimchowitsch Sarah , Moreau Catherine , Laurent Francoise , Stoeckel Marie‐Elisabeth 
Published: January 2005

AbstractThe distribution, morphological features, and morphometric characteristics of cell bodies producing oxytocin (OT) and vasopressin (AVP) were studied in the rabbit hypothalamus by means of a conventional immunoperoxidase method. The aim of the present study was to determine the existence or not of a species‐specific OT‐cell group that might be involved in the dense OT innervation of the intermediate lobe in the leporidae.No OT‐cell group clearly distinct from the hypothalamic paraventricular (PVN) and supraoptic (SON) nuclei was found, even in colchicine‐treated animals. Most immunoreactive perikarya were found within these nuclei. In addition, small AVP neurons occurred in the suprachiasmatic nucleus.In the SON, the predominant, tightly packed AVP cells occupied the ventral part of the nucleus, whereas OT neurons were dorsolaterally located. The PVN presented a loose organization without any obvious subdivision. OT cells, which predominated, occupied the medial part of the nucleus. The PVN had a prominent rostral anterobasal extension composed mainly of OT cells. Laterally to the nucleus, numerous large AVP neurons, with few and smaller OT cells, dispersed along the neurosecretory tract without forming definite cell clusters. AVP cell bodies had a rough granular aspect contrasting with the smooth and fine one of OT cells. Spinelike processes were rarely observed on the perikarya, except on large scattered AVP neurons, but frequently covered the proximal dendrites of both types of neurons. Throughout the hypothalamus, OT neurons had definitely smaller mean somal areas and were more homogeneous in size than AVP cells.