bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synaptic connections of the narrow‐field, bistratified rod amacrine cell (AII) in the rabbit retina
Authors: Strettoi Enrica , Raviola Elio , Dacheux Ramon F. 
Published: January 2005

AbstractThe synaptic connections of the narrow‐field, bistratified rod amacrine cell (All) in the inner plexiform layer (IPL) of the rabbit retina were reconstructed from electron micrographs of continuous series of thin sections. The All amacrine cell receives a large synaptic input from the axonal endings of rod bipolar cells in the most vitreal region of the IPL (sublamina b, S5) and a smaller input from axonal endings of cone bipolar cells in the scleral region of the IPL (sublamina a, S1–S2). Amacrine input, localized at multiple levels in the IPL, equals the total number of synapses received from bipolar cells.The axonal endings of cone bipolar cells represent the major target for the chemical output of the All amacrine cell: these synapses are established by the lobular appendages in sublamina a (S1–S2). Ganglion cell dendrites represent only 4% of the output of the All amacrine and most of them are also postsynaptic to the cone bipolars which receive All input. The All amacrine is not presynaptic to other amacrine cells.Finally, the AII amacrine makes gap junctions with the axonal arborizations of cone bipolars that stratify in sublamina b (S3–S4) as well as with other All amacrine cells in S5.Therefore, in the rabbit retina 1) the rod pathway consists of five neurons arranged in series: rod → rod bipolar → AII amacrine → cone bipolar → ganglion cell; 2) it seems unlikely that a class of ganglion cells exists that is exclusively devoted to scotopic functions.In ventral, midperipheral retina, about nine rod bipolar cells converge onto a single All amacrine, but one of them establishes a much higher proportion of synaptic contacts than the rest. Conversely, each rod bipolar cell diverges onto four All amacrine cells, but one of them receives the largest fraction of synapses. Thus, within the pattern of convergence and divergence suggested by population studies, preferential synaptic pathways are established. © 1992 Wiley‐Liss, Inc.
GAD‐ and GABA‐immunoreactivity in the ascending auditory pathway of horseshoe and mustached bats
Authors: Vater Marianne , Kössl Manfred , Horn Anja K. E. 
Published: January 2005

AbstractA comparative study of the immunostain to antibodies directed against glutamic acid decarboxylase (GAD) and gamma‐aminobutyric acid (GABA) in the ascending auditory pathway was carried out in horseshoe bats (Rhinolophus rouxi) and mustached bats (Pteronotus parnellii).In both species GAD/GABA‐positive puncta (presumed axonal boutons) and GAD/GABA‐positive cells were found in the cochlear nucleus, the superior olivary complex, the nuclei of the lateral lemsiscus, the inferior colliculus, and the medial geniculate body. General features of the immunostaining pattern in the auditory pathway agree with observations in other mammals, Quantitative analysis of puncta distribution shows that many auditory centers are characterized by subregional differences in puncta density and distribution. This indicates local differences in putatively inhibitory input related to connectivity and tonotopic organization.The following species characteristic features were found: 1) The dorsal non‐laminated portion of the dorsal cochlear nucleus in horseshoe bats lacks the GAD/GABA‐immunoreactive cells typical for the ventral laminated portion and the dorsal cochlear nucleus of other species. Clearly, a cytoarchitectonic specialization is accompanied by a loss of putatively GABAergic local inhibitory circuits. 2) The ventral division of the medial geniculate body of the mustached bat lacks GAD/GABA‐immunopositive cells. Such cells are present in the horseshoe bat and other mammals. This finding implies functional differences in the organization of the medial geniculate body within the same mammalian order. © 1992 Wiley‐Liss, Inc.
Fine structure of rat septohippocampal neurons: I. Identification of septohippocampal projection neurons by retrograde tracing combined with electron microscopic immunocytochemistry and intracellular staining
Authors: Naumann Thomas , Linke Rüdiger , Frotscher Michael 
Published: January 2005

AbstractIn this report the normal dendritic organization and fine structure of identified Septohippocampal projection neurons is described as a prerequisite for a time course analysis of retrograde changes in these neurons following axotomy (see Naumann et al., J. Comp. Neurol. 325:219–242, 1992). Septohippocampal projection neurons were retrogradely labeled by injection of the fluorescent tracer Fluoro‐Gold into the hippocampus. Next, retrogradely labeled cells in Vibratome sections of the medial septum/diagonal band complex were intracellularly stained with the fluorescent dye Lucifer Yellow (LY). Photooxidation of LY resulted in a stable electron‐dense reaction product, which allowed us to study these double‐labeled neurons by electron microscopy. Another series of sections containing retrogradely labeled neurons were immunostained for choline acetyltransferase (ChAT) or paryalhumin (PARV). In this way the fine structure of two different chemically characterized subpopulations of Septohippocampal neurons could be compared with that of the LY‐injected neurons.Intracellular filling of retrogradely labeled neurons with LY stained the cell body and the entire dendritic arbor. Essentially, three classes of neurons could be distinguished, i.e., bipolar cells, multipolar neurons, and an intermediate group. All these neurons displayed smooth, often varicose dendrites lacking spines. Mainly located close to the midline, there was a group of cells with only very few if any LY‐stained dendrites. In the electron microscope, the double‐labeled neurons were easily identified by numerous electron‐dense lysosomes associated with transported Fluoro‐Gold and the diffuse reaction product resulting from photooxidation. They displayed fine‐structural characteristics as previously described for cholinergic neurons. In fact, our fine‐structural analysis of ChAT‐positive Fluoro‐Gold‐labeled neurons, but also of backfilled PARV‐positive cells, gave very similar results. All these neurons had infolded nuclei, abundant cytoplasmic organelles, and a few axosomatic synapses. Thus, a plain electron microscopic study does not allow one to distinguish between subpopulations of Septohippocampal projection neurons. © 1992 Wiley‐Liss, Inc.
Fine structure of rat septohippocampal neurons: II. A time course analysis following axotomy
Authors: Naumann Thomas , Peterson Gary M. , Frotscher Michael 
Published: January 2005

AbstractPrevious light microscopic immunocytochemical studies with antibodies against transmitter‐synthesizing enzymes have suggested that septohippocampal neurons undergo retrograde degeneration following transection of their axons by cutting the fimbria‐fornix. However, a fine‐structural analysis of the degeneration process in these cells is lacking so far. Here we have identified septohippocampal neurons by retrograde tracing with Fluoro‐Gold. Thereafter, the fimbria‐fornix was transected bilaterally. Fine‐structural changes in prelabeled septohippocampal neurons were then studied after varying survival times up to 10 weeks.Examination under the fluorescence microscope of Vibratome sections through the septal region revealed numerous retrogradely labeled cells after all survival times following axotomy. These neurons were then intracellularly injected with the fluorescent dye Lucifer Yellow in order to stain their dendritic arbor. Many cells were found after each survival time that displayed characteristics of septohippocampal neurons in control rats (see Naumann et al., J Comp Neurol 325:207–218, 1992). In addition, increasing with survival time, there were many shrunken neurons with a reduced dendritic arbor. Representative examples of both normal appearing and shrunken neurons were photoconverted for subsequent electron microscopic analysis, Relatively few signs of neuronal degeneration were found at each survival time analyzed. The majority of cells, including the heavily shrunken ones, displayed fine‐structural characteristics of normal neurons, However, a few degenerating neurons and reactive glial cells were present in all survival stages.We conclude that axotomized septohippocampal projection neurons cease the expression of transmitter‐synthesizing enzymes and shrink, but many more cells survive for extended periods of time without target‐derived neurotrophic factor than was assumed in previous light microscopic studies. © 1992 Wiley‐Liss, Inc.
Neuroepithelial cells in the rat spinal cord express glutamate decarboxylase immunoreactivity in vivo and in vitro
Authors: Ma Wu , Behar Toby , Maric Dragan , Maric Irina , Barker Jeffery L. 
Published: January 2005

AbstractIt is unknown whether neuroepithelial cells in the mammalian central nervous system express neurotransmitter‐synthesizing enzymes. In this study, expression of glutamate decarboxylase (GAD), the γ‐aminobutyric acid (GABA)‐synthesizing enzyme, was examined in proliferative cells and postmitotic neuroblasts in embryonic rat spinal cord. Immunostaining coronal sections of the embryonic spinal cord with K2 antiserum, which recognizes GAD proteins encoded by the GAD67 gene, revealed intensely stained neuroepithelial cells in the basal plate at embryonic day (E) 13, in the intermediate plate between E 13–16, and last seen in the alar plate at E 16. Nissl counterstaining demonstrated that a small number of these GAD‐immunoreactive cells adjacent to the neural tube lumen were mitotic. The ventral‐to‐dorsal gradient of GAD expression in precursor cells and postmitotic neuroblasts correlates anatomically and temporally with the sequential generation of motoneurons, commissural neurons, and interneurons in the dorsal horn. Some of these GAD‐immunoreactive neuroepithelial cells may re‐enter the mitotic cycle, while others are postmitotic neuroblasts presumably migrating to the intermediate zone to differentiate into young neurons. Double‐immunostaining cells acutely dissociated from E 11–18 spinal cords with K2 and anti‐bromodeoxyuridine antisera, following a bromodeoxyuridine pulse in vivo, revealed considerable numbers of DNA‐synthesizing cells immunoreactive for GAD. The absolute number of double‐stained cells peaked during E 12–15, coinciding with terminal cell division in most spinal neurons. These observations suggest that spinal neuronal precursors can synthesize GAD‐related proteins prior to, or during, the terminal cell cycle. Although GAD immunoreactivity revealed by K2 antiserum was detected in proliferative cells and in migrating postmitotic neuroblasts, GABA immunoreactivity was never detectable in these cells. These early embryonic GAD‐immunoreactive neuroepithelial cells may either synthesize levels of GABA that cannot be detected immunocytochemically, and/or express enzymatically inactive GAD‐related proteins. © 1992 Wiley‐Liss, Inc.
Unique topographic separation of two spectral classes of cones in the mouse retina
Authors: Szél Á. , Röhlich P. , Gaffé A. R. , Juliusson B. , Aguirre G. , Van Veen T. 
Published: January 2005

AbstractWe have found two immunologically distinguishable cone types in the retina of the mouse, each localized to two opposite halves of the eye. One cone type was labelled by the monoclonal antibody COS‐1 specific to the middle‐to‐long wave sensitive visual pigment of the mammals, while the other type was stained by the shortwave‐specific monoclonal antibody (OS‐2). These results were confirmed with other antibodies directed against specific sequences of the visual pigments. As a result of the uneven distribution of the two cone types the mouse retina is divided into two fields separated by an oblique meridional line. The middlewave sensitive cones were present exclusively in the dorsal half of the mouse retina (M‐field). The overwhelming majority of the shortwave sensitive cones occupied the ventral half (S‐field), and only a small number was scattered among the middlewave sensitive cones in the dorsal retina. The ratio of the two cone types in the M‐field corresponds to what has been found in the retina of other mammals, including rodents such as the gerbil and the rat. The S‐field represents an entirely unique area with the unusually great number of shortwave sensitive cones and with the complete lack of the middlewave sensitive ones.The present study provides the structural basis for dichromacy in a rodent species considered for a long time to be monochromat. In addition, it shows that the ventral retina, containing exclusively S‐cones in a relatively high density, is a unique retinal field not present in other mammalian species studied so far. © 1992 Wiley‐Liss, Inc.
Central projections and motor nuclei of the facial, glossopharyngeal, and vagus nerves in the mormyrid fish Gnathonemus petersii
Authors: Lazar G. , Szabo T. , Libouban S. , Ravaille‐veron M. , Toth P. , Brändle K. 
Published: January 2005

AbstractMost of the information about the anatomy of the fish's cranial nerves was collected in the first two decades of this century. Experimental analysis of the VIIth, IXth, and Xth cranial nerves by modern tract tracing techniques started about 20 years ago. Several species have been investigated to date, including one species of Agnatha (Myxinoidea), two species of elasmo‐branchs, and species of some orders of Teleostei like Cyprinidae, Siluriformes, Perciformes, and Gadidae.The Sensory and motor nuclei of the VIIth, IXth, and Xth cranial nerves of Gnathonemus petersii were studied by anterograde and retrograde axoplasmatic transport of horseradish peroxidase and cobaltous lysine complex. The sensory nuclei form a continuous column of cells in the brain stem extending caudal to the obex. The rostral one‐fourth of this column is occupied by the overlapping terminals of the VIIth and IXth nerves. The vagus nerve has 5 roots. The first 4 of these innervate the gills and the fifth supplies viscera. Afferents from the gills terminate ipsilaterally rostral to the obex in topographic order and their terminal fields overlap. Viscerosensory fibers terminate ipsilaterally in the obex region and bilaterally in the commissural nucleus of Cajal.The facial motor nucleus is located rostral to the sensory nucleus. Facial motoneurons have pear‐shaped and multipolar perikarya. Their axons form a rostrally directed knee before leaving the brain. The motoneurons of the IXth and Xth nerves have a common cell column. The vagal motoneurons form a periventricular, a medial, and an intermediate cell group rostral to the obex. In the obex region and also caudal to it, a lateral and a caudal group can be distinguished. Vagal motoneurons show a topographic arrangement that is similar to that of the sensory vagal projections. The majority of motoneurons have pear‐shaped perikarya and ventrolaterally oriented dendrites. In the caudal nucleus the dendrites extend dorsally and overlap the terminals of sensory fibers. The axons form a dorsolaterally directed arch before joining the sensory roots.Since G. petersii uses its electrosensory system primarily for detection of food, its gustatory system is less developed than in other fishes, which possess a large number of taste buds. © 1992 Wiley‐Liss, Inc.
Cytoarchitectonic organization and morphology of cells of the field L complex in male zebra finches (taenopygia guttata)
Authors: Fortune Eric S. , Margoliash Daniel 
Published: January 2005

AbstractThe organization of the field L complex, a thalamorecipient auditory region in the telencephalon of birds, was examined in Nissl and Golgi preparations of male zebra finches (Taenopygia guttata). The field L complex comprises five cytoarchitectonic subdivisions: L1, L2a, L2b, L3, and L, although the border between L and L2b is not distinct. L2a is a plate extending dorsocaudally from the dorsal medullary lamina in the caudal neostriatum. L1 lies on the anterodorsal border and L3 lies on the posteroventral border of L2a. L, the area designated “field L” by Rose (J. Psychol. Neurol., 1914, 2:278–352), forms the medial and posterior borders of the field L complex, L2b is a thick band that forms the dorsal and dorsolateral boundary of the field L complex and is continuous with L medially. Nucleus interface (NIf) is a nucleus that lies between L2a and L1 near the lateral edge of the complex.The four types of Golgi stained neurons that occur in the zebra finch field L complex correspond to those described for the European starling (Sturnus vulgaris). Additionally, type 3 neurons are subdivided into “unoriented” neurons with spherical dendritic fields and “oriented” neurons with bipolar dendritic fields. NIf contains a distinct class of neurons that have large somata with both thick and thin spiny dendrites. The distribution of Golgi cell types between the subdivisions of the field L complex corresponds to the morphology of cells seen in Nissl material. Type 3 oriented cells are found almost exclusively within L2a. L3 has significantly greater numbers of the largest cells (type 1) and significantly smaller numbers of the smallest cells (type 4) than does LI. There are no significant differences in the distribution of Golgi stained cells between L2b and L. © 1992 Wiley‐Liss, Inc.
Design and control of the head retractor muscle in a turtle, Pseudemys (trachemys) scripta: II. Efferent innervation
Authors: Callister R. J. , Peterson E. H. 
Published: January 2005

AbstractThe head retractor muscle (RCCQ) of Pseudemys scripta is a useful model in which to study the mechanisms animals use to vary the force and timing of movement. Single fibers in this muscle differ significantly in attachments, length, diameter, taper characteristics, and histochemical properties, suggesting that they may be energetically and architecturally specialized for different roles in head movement. In the present paper, we report the peripheral and central efferent innervation of these diverse muscle cells, and we ask how the design of the neural apparatus is matched to the properties of its target muscle fibers.Three out of four bellies in RCCQ are supplied by multiple segmental nerves. The territories of these nerves are separated rostrocaudally within the muscle belly; thus, long muscle fibers cross the territories of two or more segmental nerves. Motor terminals in RCCQ resemble those on frog twitch muscles. Their sizes (length, bouton number) are correlated with the diameters of their target muscle fibers. Each muscle fiber bears 2–14 terminals evenly spaced (approx. 5 mm apart) along its length. Thus, single muscle fibers in RCCQ are multiterminally, and long fibers are multisegmentally innervated. Control experiments indicate that the axons in each segmental nerve arise from different motor neuron populations. Thus, short, in‐series fibers are supplied by different motor neurons, and individual long fibers in RCCQ are polyneuronally innervated. These data help explain how long muscle fibers with relatively slow conduction speeds can generate rapid head movements, and they raise questions about the central mechanisms that coordinate the recruitment of RCCQ motor neurons. © 1992 Wiley‐Liss, Inc.
Development of commissural neurons in the embryonic rat spinal cord
Authors: Silos‐Santiago Inmaculada , Snider William D. 
Published: January 2005

AbstractLittle is known about the development of the various populations of interneurons in the mammalian spinal cord. We have utilized the lipid‐soluble tracer DiI in fixed tissue to study the migration and dendritic arborization of spinal neurons with axons in the ventral commissure in embryonic rats. Crystals of DiI were placed in various locations in the thoracic spinal cord in order to label commissural neurons within the dorsal horn, intermediate zone, and ventral horn at E13.5, E15, E17, and E19.Seven different groups of commissural interneurons are present in the spinal cord by E13.5. Migration is relatively simple with groups occupying a position along the dorsoventral axis roughly corresponding to their position of origin along the neuroepithelium. By E15, commissural cells are near their final locations and exhibit characteristic morphology. One striking feature is the tendency of cells with similar morphology to cluster in distinct groups. By E19, at least 18 different types of commissural interneurons can be identified on morphological grounds. Although the situation is complex, some generalities about dendritic morphology are apparent. Commissural neurons located in the dorsal horn are small and have highly branched dendrites oriented along the dorsoventral axis. In more ventral regions, commissural neurons are larger and possess dendritic arbors oriented obliquely or parallel to the mediolateral axis with long dendrites extending toward the lateral and ventral funiculi. The number of primary dendrites of most groups is set by E15 and dendritic growth occurs in the transverse plane by lengthening and branching of these primary processes.This study demonstrates that a large number of classes of commissural interneurons can be recognized on the basis of characteristic morphologies and locations within the dorsal horn, intermediate zone and ventral horn of the embryonic rat spinal cord. This finding is consistent with the fact that commissural neurons project to many different targets and mediate a variety of different functions. The demonstration that dendritic arbors of spinal interneurons with characteristic morphologies can be conveniently labelled with DiI should prove useful in future studies on the development of specific circuits in the mammalian spinal cord. © 1992 Wiley‐Liss, Inc.