bluuebunny/crossref_metadata_2025_split huggingface dataset:
Projections from the cochlear nuclei in the mustache bat, Pteronotus parnellii
Authors: Zook J. M. , Casseday J. H. 
Published: January 2005

AbstractAscending projections of the cochlear nuclei in the mustache bat were analyzed by anterograde transport of [3H]‐leucine and by retrograde transport of HRP. We were particularly interested in pathways to two parts of the system: (1) to the medial superior olive, because this nucleus is missing in most echolocating bats, but appears to be present in the mustache bat, and (2) to the intermediate and ventral nuclei of the lateral lemniscus, because these nuclei are hypertrophied and highly differentiated in all echolocating bats that we have examined. The results show a highly systematic projection from the anteroventral cochlear nucleus to all of the auditory nuclei in the brain stem. After an injection of [3H]‐leucine in the anterior and dorsal part of the anteroventral cochlear nucleus, presumably in a region sensitive to low frequencies, label is seen in the following locations: ipsilateral to the injection in the lateral part of the lateral superior olive; bilaterally in the dorsal part of the medial superior olive; contralateral to the injection in the dorsal parts of the intermediate and ventral nuclei of the lateral lemniscus; and in the anterolateral part of the central nucleus of the inferior colliculus. After an injection of [3H]‐leucine in a posterior part of the anteroventral cochlear nucleus, presumably in a region sensitive to high frequencies, labeling is in the same set of nuclei, but within each nucleus the label is now in a different location; medially in the lateral superior olive, ventrally in the medial superior olive, ventrally in each division of the ventral and intermediate nuclei of the lateral lemniscus, and medially in the central nucleus of the inferior colliculus. Projections from the entire anteroventral cochlear nucleus to the inferior colliculus are confined to the ventral two‐thirds of the central nucleus. The dorsal one‐third of the central nucleus of the inferior colliculus is the principal target of the dorsal cochlear nucleus and may be a target of the posteroventral cochlear nucleus. Both of these nuclei appear to project sparsely to the ventral parts of the inferior colliculus.We conclude first that the bilateral input to the medial superior olive in the mustache bat is similar to the input seen in other mammals. Thus this bat has a neural structure which is associated with the analysis of binaural time differences and which usually is seen only in animals with heads large enough to create interaural time differences greater than those available to Pteronotus. Second, the projections from the anteroventral cochlear nucleus diverge to three separate targets in the lateral lemniscus: one in the intermediate nucleus and two in the ventral nucleus of the lateral lemniscus. These three target areas of the lateral lemniscus then project as three parallel pathways to the inferior colliculus.
Projection systems and terminal localization of dorsal column afferents: An autoradiographic and horseradish peroxidase study in the rat
Authors: Massopust L. C. , Hauge D. H. , Ferneding J. C. , Doubek W. G. , Taylor J. J. 
Published: January 2005

AbstractProjection systems from the gracile nucleus and the cuneate nuclear complex to their terminal sites in the mesencephalon, diencephalon, and cerebellum were examined by means of anterograde autoradiography and retrograde horseradish peroxidase methods.Three projection systems emerge from the dorsal column nuclei, decussate via internal arcuate fibers, and form the contralateral medial lemniscus (ML). At the obex, some fibers split off the ML and course dorsolaterally, forming an ascending lateral system which fits the “lemniscal adjunct channel” (LAC) concept of Graybiel ('72). The ML continues rostrally as the “main lemniscal line channel” (MLLC). At the inferior colliculus, some LAC fibers terminate in the pontine nuclei, parabrachial, dorsal reticular nuclei, and the external and ventral medial part of the central nucleus of the inferior colliculus. More rostrally at the level of the superior colliculus, terminal fields are found in the medial nucleus of the medial geniculate body, the suprageniculate, pretectal, and mesencephalic reticular nuclei, marking the end of the LAC. In the diencephalon, gracile fibers leave the MLLC and form a crescentlike terminal field along the extreme lateral border of the ventral posterior lateral nucleus (VPL) of the thalamus. Cuneate MLLC fibers terminate in a bandlike formation in the VPL medial to the gracile termination.The third fiber system, the cuneocerebellar projection, emerges from the cuneate, the external cuneate nuclei, and the “cellular bridge” and immediately enters the ipsilateral inferior cerebellar peduncle. Upon entering the cerebellum, the major fiber component remains ipsilateral and terminates as vertical bands in vermal and paravermal lobules, and lobules I through IVa. The posterior cerebellar lobe contains terminal bands in lobules VII–IX, the copula pyramidis, and the paramedian lobule.It is concluded that the dorsolateral fiber system conforms to Graybiel's LAC. It is more divergent and probably less modality specific, whereas the medial lemniscal system conforms to the MLLC, which is said to be modality specific, less divergent, and locked to specific sensory‐motor response characteristics.The topography of cerebellar terminal bands indicates that there is sensory‐motor representation from all parts of the body to all parts of the cerebellum, at least in the rat.
The afferent and sympathetic components of the lumbar spinal outflow to the colon and pelvic organs in the cat. I. The hypogastric nerve
Authors: Baron R. , Jänig W. , McLachlan Elspeth M. 
Published: January 2005

AbstractThe cell bodies of the lumbar sensory and sympathetic pre‐ and postganglionic neurons that project to the pelvic organs in the hypogastric nerve of the cat have been labeled retrogradely with horseradish peroxidase applied to the central end of their cut axons. The numbers, segmental distribution, location, and size of these labeled somata have been determined quantitatively. Afferent and preganglionic cell bodies were located bilaterally in dorsal root ganglia and spinal cord segments L3–L5, with the maximum numbers in L4. Very few cells lay rostral to L3. Afferent cell bodies were generally very small in cross‐sectional area relative to the entire population in the dorsal root ganglia. Most of the preganglionic cell bodies lay clustered just medial to the region of the intermediolateral column and extended caudally well beyond its usual limit in the upper part of L4. These neurons were, on the average, larger than the cells of the intermediolateral column itself, with the largest cells lying in the most medial positions. Most of the post‐ganglionic somata were in the ipsilateral distal lobe of the inferior mesenteric ganglion, while some (usually < 10%) lay in accessory ganglia along the lumbar splanchnic nerves and in paravertebral ganglia L3–L5. Postganglionic somata in the inferior mesenteric ganglion were larger than both labeled and unlabeled ganglion cells in the paravertebral ganglia. From the data, it is estimated that about 1,300 afferent neurons, about 1,700 preganglionic neurons, and about 17,000 postganglionic neurons project in each hypogastric nerve in the cat.
Somatostatin‐Like immunoreactivity in neurons, nerve terminals, and fibers of the cat spinal cord
Authors: Krukoff Teresa L. , Ciriello John , Calaresu Franco R. 
Published: January 2005

AbstractThe distribution of somatostatin‐like immunoreactivity (SS) was studied in the spinal cord of untreated cats and of cats that had received colchicine at all levels of the cord. In the dorsal horn small (less than 15 μm in diameter), round neurons were found in Rexed laminae II and III at all levels. At all levels laminae IV‐VI contained smaller numbers of immunoreactive neurons that were medium (between 15 and 25μm in diameter) to large (greater than 25μm in diameter) in size. In addition small numbers of medium‐sized neurons were observed at the dorsal and dorsomedial borders of the gray and white matter in segments C1‐5. In the sacral cord (Sl‐3), a group of medium‐sized bipolar neurons was found in the dorsolateral funiculus. In transverse sections the processes of the neurons in these two latter groups travelled in a direction parallel to the border of the gray and white matter. In the intermediate and central gray matter, in addition to the immunoreactive neurons found in the region of the intermediolateral nucleus and nucleus intercalatus of lamina VII in segments C8 to L4 (Krukoff et al., '85a), lamina VII contained immunoreactive neurons at all levels with the largest number occurring in the thoracic cord. These neurons were medium to large in size and were generally multipolar with processes travelling in all directions. Multipolar small immunoreactive neurons were also found in the central gray region (lamina X) in the thoracic and upper lumbar cord. Finally, small numbers of neurons containing SS were found in the ventral horn of the cervical and upper thoracic cord. These multipolar neurons were medium to large in size. The distribution of nerve terminals and fibers containing SS was similar to that previously described in mice, rats, guinea pigs, and primates. Although the function of somatostatin in the spinal cord is not known, its presence in neurons with short processes suggests that it may act to modify local activity in the regions where it is found, including areas involved in sensory, visceromotor, and motor functions.
The cholinergic innervation of the rat fascia dentata: Identification of target structures on granule cells by combining choline acetyltransferase immunocytochemistry and Golgi impregnation
Authors: Frotscher Michael , Léránth Csaba 
Published: January 2005

AbstractA monoclonal antibody against choline acetyltransferase (ChAT), the acetylcholine‐synthesizing enzyme, was used to study cholinergic synagses on identified (Golgi stained) granule cells in the rat fascia dentata. Choline acetyltransferase immunocytochemistry was applied to 40‐μm Vibratome sections cut perpendicular to the longitudinal axis of the hippocampus. Light microscopy revealed fine varicose ChAT‐immunoreactive axons in all layers of the fascia dentata, i.e., in the stratum moleculare, the stratum granu‐losum, and the subgranular polymorph zone. Most fibers were observed in the vicinity of granule cell bodies where they ran mainly parallel to the granular layer. Next, the immunostained Vibratome sections were sandwiched between small pieces of Parafilm and piled to form a block that was covered with agar and Golgi stained. After that, the sections were separated by cutting away the agar and removing the Parafilm. Sections containing well‐impregnated granule cells were gold‐toned (Fairén et al., '77), embedded in Araldite, and subjected to ultrathin sectioning for electron microscopy. A total of 14 gold‐toned granule cells were examined in the electron microscope for synaptic contacts with cholinergic afferents. Choline acetyltransferase‐immunoreactive axon terminals were observed that established symmetric synaptic contacts with the cell bodies and dendritic shafts of the gold‐toned identified granule cells. Two types of contact were observed on spines arising from gold‐toned granule cell dendrites. Immunoreactive terminals established asymmetric synaptic contacts with the head of small spines and symmetric contacts with the stalk of large, complex spines. The boutons forming asymmetric synaptic contacts with the cup‐shaped spine head of the complex spines were not found to be immunoreactive. Our results demonstrate that cholinergic fibers to the rat fascia dentata establish characteristic types of synaptic contact with different postsynaptic elements of granule cells, suggesting a complex function of this afferent system.
Anatomical studies on the nucleus reticularis tegmenti pontis in the pigmented rat. II. Subcortical afferents demonstrated by the retrograde transport of horseradish peroxidase
Authors: Torigoe Yasuhiro , Blanks Robert H. I. , Precht Wolfgang 
Published: January 2005

AbstractThe subcortical nuclear groups projecting to the nucleus reticularis tegmenti pontis (NRTP) were studied in pigmented rats with the aid of the retrograde horseradish peroxidase (HRP) technique. Small iontophoretic injections of HRP were placed in the medial regions of the NRTP, an area that has been shown in several species to be involved in eye movements. Other large injections in the NRTP or small injections placed just outside the nucleus were used to clarify the projections to the NRTP. Results indicate that the NRTP receives afferents from (1) visual relay nuclei, including the nucleus of optic tract, the superior colliculus, and the ventral lateral geniculate nucleus; (2) oculomotor‐associated structures including the zona incerta, the H1 and H2 fields of Forel, the nucleus subparafasciculus, the interstitial nucleus of Cajal, the visual tegmental relay zone of the ventral tegmental area of Tsai, the mesencephalic, pontine, and medullary reticular formations, the nucleus of the posterior commissure, and a portion of the periaqueductal gray termed the supra‐oculomotor periaqueductal gray; (3) cerebellar and pontomedullary nuclei, including the superior, lateral, and medial vestibular nuclei, the deep cerebellar nuclei, and NRTP interneurons, and (4) nuclei related to limbic functions including the lateral habenula, the mammillary nuclei, the hypothalamic nuclei, the preoptic nuclei, and the nucleus of diagonal band of Broca.A surprisingly large number of afferents to the medial regions of the NRTP arise from visual‐ or eye‐movement‐related nuclei. The projection from the nucleus of the optic tract (NOT) confirms previous anatomical and physiological studies on the pathways involved in horizontal optokinetic nystagmus, but the number of NOT afferents is small in relation to other areas potentially related to visuomotor pathways such as the zona incerta, ventral lateral geniculate nucleus, fields of Forel, perirubral area, and subparafasciculus. The NRTP may also relay information related to vertical visuomotor reflexes (e.g., vertical optokinetic nystagmus) given the strong projections from the medial terminal nucleus of the accessory otpic system, visual tegmental relay zone, supra‐oculomotor periaqueductal gray, interstitial n. of Cajal, and midbrain reticular formation. The presence of significant NRTP projections from the superior colliculus and the mesencephalic and pontine reticular formations suggests that these nuclei may provide the pathways for the noted saccade‐related activity of NRTP neurons. In addition, projections from the vestibular nuclei were found that provide the anatomical basis for head velocity signals recorded in NRTP neurons. Lastly, the dense labeling within the deep cerebellar nuclei, most notably the dentate nucleus, confirms previous reports that the NRTP is intimately involved in the feedback control of cerebellar function.
Organization of the efferent, vestibular nuclei and nerves of the toadfish, Opsanus tau
Authors: Highstein Stephen M. , Baker Robert 
Published: January 2005

AbstractThe efferent vestibular nuclei and nerves were studied in the toadfish, Opsanus tau, with morphological and electrophysiological techniques. The origin and course of the efferent vestibular nerves was extensively documented. One major morphological observation was that the efferent nerves comprise a peripheral network that is anatomically distinct, and separable by dissection from the primary afferents innervated by each end organ. These anatomically distinct nerves are likely to be a major asset in physiological studies of efferent vestibular function. The retrograde transport of horseradish peroxidase (HRP) from each of the nerves innervating the vestibular and lateral line organs was used to delineate the subgroups of efferent neurons projecting to these end organs. The efferent vestibular nuclei are located in the posterior medulla in and around the median longitudinal fasiculi (MLF). We divided the nuclei cytoarchitecturally into lateral, medial, and' dorsal subdivisions. The lateral cells had bilateral dendritic trees while the dorsal cells had ipsilateral, unilateral dendritic trees. There was a higher proportion of lateral cells that innervated the canal organs and the utricle while the dorsal cells tended to innervate the other organs. The total number of cells obtained by summing those from separate nerve label was twice the total cell count present in the nuclei. Indirectly, this indicates that some cells project to more than one end organ. Efferent neurons were penetrated with glass microelectrodes, and their end organs and patterns of connectivity with other end organs were investigated by stimulating various vestibular nerves. Posterior semicircular canal efferent cells are electrically coupled to each other and could be activated electrically or chemically by stimulating other ipsilateral or contralateral vestibular nerves. It is suggested that electrical coupling might be responsible for the uniform behavior of these cells under certain conditions. Morphological and physiological experiments suggested that the semicircular canals are innervated by their own, exclusive populations of efferent neurons while other end organs may share efferent innervation. Single cells were injected intracellularly with HRP and their morphology was studied and characterized by light microscopy. Intracellular label confirmed the morphological features demonstrated by retrograde transport of HRP and also revealed that some cells had central axon collaterals that terminated within the MLF. These morphological and physiological results provide a basis for understanding the behavior of efferent vestibular neurons in the alert animal.
A new enzyme marker for striatal compartmentalization: NADPH diaphorase activity in the caudate nucleus and putamen of the cat
Authors: Sandell Julie H. , Graybiel Ann M. , Chesselet Marie‐Françcoise 
Published: January 2005

AbstractThe distribution of dihydronicotinamide adenine dinucleotide phosphate diaphorase (NADPH diaphorase) was studied by enzyme histochemistry in the striatum of the adult cat. Neurons and neuropil expressing NADPH diaphorase activity were found throughout, the striatum. The diaphorasepositive neurons formed a sparse population of medium‐sized cells. In the caudate nucleus they were recognized by antisera against somatostatin 14, somatostatin 28(1‐12), neuropeptide Y and avian pancreatic polypeptide. The diaphorase activity of the striatal neuropil was characterized by a modular organization that was particularly distinct in the caudate nucleus. This organization was analyzed by comparing the patterns of diaphorase staining with the distribution of acetylcholinesterase activity in adjacent sections. The NADPH diaphorase activity was found to be dense in the acetylcholinesterase‐rich matrix of the caudate nucleus, but weak in the acetylcholinesterase‐poor compartments known as striosomes.Because of the colocalization of perikaryal NADPH diaphorase activity and somatostatinlike immunoreactivity, a comparison was also made between the distribution of diaphorase staining and immunostaining for somatostatinlike peptide in the striatal neuropil. Both observed striosomal ordering, so that the acetylcholinesterase‐poor zones detected in adjoining sections corresponded to regions of low somatostatinlike immunoreactivity as well as low NADPH diaphorase staining. In some regions striosomes were more clearly delineated in the stains for diaphorase and somatostatinlike immunoreactivity than in the acetylcholinesterase stain. These observations suggest that NADPH diaphorase may be a sensitive marker for the somatostatinergic neuropil as well as the somatostatinergic perikarya of the striatum, and that this enzyme could prove valuable in attempts to differentiate the processes of intrinsic somatostatin‐containing fibers from any extrinsic somatostatin afferents that may exist.
An ultrastructural study of interplexiform cell synapses in the human retina
Authors: Linberg Kenneth A. , Fisher Steven K. 
Published: January 2005

AbstractUsing serial sections and electron microscopy, we have found several morphological types of synapses within the outer plexiform layer (OPL) of the human retina. The most conspicuous of these is described in this paper. They have a unique morphology and form synapses with rod and cone bipolar cells in the OPL and onto bipolar and amacrine cell bodies in the inner, nuclear layer (INL). Because they occur in processes that extend across the INL, we believe these synapses are made by interplexiform cells (IPCs). These same processes also contact cone pedicles with specialized cell junctions like those made between cones and flat bipolars. These junctions have densification of both cell membranes and widening of the extracellular cleft, but no accumulation of synaptic vesicles. Similar‐appearing processes in the inner plexiform layer are thought to belong to IPCs but their contacts were less completely identified. Possible circuitry for these IPCs is described and the possibility that there are different classes of IPCs in the human retina is discussed.The OPL forms in the posterior retina during the tenth fetal week. Our observations suggest that different types of synapses including those of the IPCs are present in this layer from the time of its first appearance.
Morphology and synaptic connections of myelinated primary axons in the ventrolateral region of rat trigeminal nucleus oralis
Authors: Falls William M. 
Published: January 2005

AbstractNeurons in the ventrolateral (VL) subdivision of rat trigeminal nucleus oralis (Vo) have most of their dendritic arbors confined within this region. This study examines the morphology and synaptic connections of a population of myelinated primary trigeminal axons that arborize within VL and are in a position to provide input directly to VL neurons. Primary axons were visualized for light and electron microscopic analysis by injecting 30% horseradish peroxidase (HRP) in 2% dimethylsulfoxide (DMSO) into the sensory root of the trigeminal nerve and allowing 24–36 hours for the anterograde transport of HRP into the terminal axonal arbors. This population is characterized by its cone‐shaped terminal arbors, which generate many axonal endings (2–8 μm in diameter) along unmyelinated terminal strands. These arbor s arise from collaterals emanating from thinly myelinated (2–5 μm in diameter) parent branches descending in the spinal V tract, which, on the basis of their size, are considered to be small myelinated (As) primary trigeminal axons.HRP‐labeled P endings belonging to this population of primary axons are scalloped, filled with spherical to ovoid (40–70 nm in diameter) synaptic vesicles, and lie centrally in glomeruli where they make asymmetrical axodendritic synapses on dendritic shafts and spine heads. It is at these synapses that this population of primary trigeminal axons is probably transferring its input directly to the dendritic arbors of VL neurons. The dendritic shafts and spine heads also receive symmetrical to intermediate axodendritic synapses from endings containing flattened (70 × 29 nm) synaptic vesicles. These terminals also establish axo‐axonic synapses on the P ending. Other synaptic components found less often in the glomeruli include small terminals containing oval (14–23 nm) synaptic vesicles that establish symmetrical to intermediate synapses on the P. ending, boutons containing pleomorphic (35–80 nm) synaptic vesicles that form symmetrical to intermediate synapses on the P ending as well as on dendritic shafts, and small peripheral endings containing round (20–40 nm) synaptic vesicles that establish asymmetrical synapses on dendritic shafts.