bluuebunny/crossref_metadata_2025_split huggingface dataset:
Anatomy of physiologically identified eye‐movement‐related pause neurons in the cat: Pontomedullary region
Authors: Ohgaki Tohru , Curthoys Ian S. , Markham Charles H. 
Published: January 2005

AbstractPause neurons (PNs) are inhibitory neurons close to the midline at the pontomedullary junction that fire tonically and then cease firing just prior to quick eye movements of visual or vestibular origin. Previous physiological evidence has shown that these neurons have a role of central importance in the generation of rapid eye movements in any direction and all major models of ocular motor control incorporate PNs as major elements. In this study in cats, we injected horseradish peroxidase intracellularly into somata or axons of physiologically identified PNs. After appropriate tissue preparation, cell body and axonal reconstructions were performed, with the aid of a camera lucida‐equipped microscope. Fifty‐three PNs were stained and reconstructed. These consisted of 17 cell bodies and dendrites and 36 axons. Seven of these included both cell bodies and axons. PN somas lay close to the midline in the nucleus raphe pontis and centralis superior, had extensive dendritic arborizations tending to arise from either pole of the elongated soma, and had axons which typically crossed the midline and bifurcated into long branches which extended rostrally and caudally, inferior to the medial longitudinal fasciculus. There were major terminal arborizations and boutons in areas just rostral and caudal to the abducens nucleus in areas where two types of premotor neurons, excitatory and inhibitory burst neurons, are concentrated. Many axosomatic contacts were noted. Other terminal arborizations and boutons were found close to the midline in a region rostral to abducens nucleus containing other neurons known to burst prior to quick eye movements, and in the nucleus reticularis gigantocellularis. Rostral stem axons could be traced to the level of the trochlear nucleus and inferior to the medial longitudinal fasciculus. The caudal stem axons could be traced parallel to the midline and inferior to the medial longitudinal fasciculus and as far caudally as the hypoglossal nucleus.
Organization of cortical and subcortical projections to area 6m of the cat
Authors: Olson C. R. , Jeffers I. 
Published: January 2005

AbstractBy analyzing regional variations of afferent connectivity, we have identified a medial subdivision of feline area 6 (area 6m) which differs from all surrounding sectors of the frontal lobe in its pattern of inputs. Area 6m is located in the ventral bank of the cruciate sulcus and on the adjacent medial face of the frontal, lobe and is partially coextensive with the medial frontal eye field as identified previously in electrophysiological experiments.Area 6m is innervated by axons from visual, association, and oculomotor areas and does not receive projections from somesthetic or somatomotor areas. Cortical sources of input to area 6m include several retinotopically organized extrastriate visual areas (AMLS, ALLS, and PLLS), association areas with strong links to the visual system (area 7, granular insula, posterior ectosylvian gyrus, and cingulate gyrus), and a lateral division of area 6 (area 6l) with oculomotor functions. Thalamic afferents of area 6m derive from the paralamellar ventral anterior nucleus, from a dorsolateral division of the mediodorsal nucleus, and from the rostral intralaminar nuclei. The claustrum and the basolateral nucleus of the amygdala project to area 6m. Projections from area 7, the posterior cingulate area, the ventral anterior nucleus, and the mediodorsal nucleus are spatially ordered in a pattern such that parts of area 6 close to the fundus of the cruciate sulcus receive input from neurons positioned anteriorly in the cortical areas, dorsolaterally in the ventral anterior nucleus, and ventrolaterally in the mediodorsal nucleus.Our results indicate that area 6m probably is involved in the voluntary control of gaze and attention rather than in skeletomotor functions.
Thalamic projections to the hippocampal and entorhinal areas in the cat
Authors: Yanagihara Mamoru , Niimi Kahee , Ono Katsuhiko 
Published: January 2005

AbstractThe thalamic projections to the hippocampal formation and to the subicular and entorhinal areas in the cat have been studied with retrograde transport of horseradish peroxidase (HRP) or wheat germ agglutinin conjugated to HRP (WGA‐HRP) and anterograde transport of WGA‐HRP. Retrograde transport tracers injected in various parts of these cortices resulted in labeled cells in the midline, anterior, and lateral dorsal nuclei. Injections into the hippocampal formation or the subiculum led to retrograde labeling of cells in the reuniens nucleus of the ipsilateral thalamus throughout its rostrocaudal extent, whereas the restricted injections into the dentate gyrus and the inferior region of the hippocampus led to no labeling. Following an injection into the pre‐ and parasubiculum, a large number of labeled cells were seen not only in the reuniens nucleus but in other midline nuclei. In addition, a substantial number of labeled cells were also detected in the anterior and lateral dorsal nuclei, particularly in the anterodorsal nucleus, which contained densely arranged labeled cells throughout almost the entire rostrocaudal extent. An injection into the medial entorhinal area labeled a number of cells in the anterior nuclei and in the reuniens nucleus, particularly its dorsal part. Injections into various subdivisions of the lateral entorhinal area yielded different patterns of distribution of labeled cells in the thalamic nuclei. An injection into the ventromedial division (VMEA) led to abundant labeling of cells in the paraventricular and reuniens nuclei. After an injection into the ventral division (VLEA), numerous labeled cells were detected in the reuniens nucleus and a lesser number in the paraventricular nucleus at anterior levels. When an injection was made into the dorsal division (DLEA), a large number of labeled cells were detected in the reuniens nucleus, and less numerous labeled cells were found in the central medial nucleus. There appears to be a topographic arrangement of cortical projections of the reuniens nucleus. The pre‐ and parasubiculum receive projections from the most medial part of the reuniens nucleus near the midline, and the DLEA receives projections from the medial part of the nucleus. The cells projecting to the VLEA and MEA are distributed in the central part of the reuniens nucleus, and those to the VMEA are distributed in the lateral part. Anterograde experiments were also performed; injections of WGA‐HRP into the reuniens nucleus resulted in terminal labeling in the superficial layers of the subicular area and the neighboring hippocampus and in the entorhinal area.
Retinohypothalamic projection and suprachiasmatic nucleus of the house sparrow, Passer domesticus
Authors: Cassone Vincent M. , Moore Robert Y. 
Published: January 2005

AbstractThe distribution of retinohypothalamic projections and the organization of the suprachiasmatic region of the hypothalamus was investigated in the house sparrow (Passer domesticus). Retinohypothalamic projections (RHT) were studied by two anterograde tracing methods, and hypothalamic organization was investigated immunohistochemically with antisera against a number of substances known to be present in the mammalian suprachiasmatic nucleus (SCN): bombesin (BBS), glutamic acid decarboxylase (GAD), 5‐hydroxytryptamine (5HT), neuropeptide Y (NPY), neurotensin (NT), somatostatin (SS), substance P (SP), vasoactive intestinal polypeptide (VIP), and arginine vasopressin (AVP). Observations from these experiments were analysed within the framework of a cytoarchitectural study using Nissl‐stained material.From this study, we have identified an area in the anterior hypothalamus which we believe is an avian homologue of the mammalian SCN. This area contains a nucleus located in close apposition to the optic chiasm between the dorsal supraoptic decussation (DSD) and the ventral lateral geniculate body (GLv) for much of its rostrocaudal extent. The central portion of this nucleus contains neurons that exhibit GAD‐ and BBS‐like immunoreactivity and is the terminal field for the RHT. For this reason, we term this nucleus the visual SCN. It also contains axon plexuses exhibiting 5HT‐like, SP‐like, and NPY‐like immunoreactivity and is bordered ventrally by AVP‐like, SP‐like, and NT‐like immunoreactive cells and medially by VIP‐like and SS‐like immunoreactive cells. Although it is not established that these cell groups together compose a single suprachiasmatic nucleus, the organization in the avian brain of a nuclear complex with a retinorecipient area surrounded by nonvisual components would be very similar to that of the mammalian SCN.
Deafferentation‐induced alterations in the rat dorsal horn: I. Comparison of peripheral nerve injury vs. rhizotomy effects on presynaptic, postsynaptic, and Glial processes
Authors: Kapadia Shanta E. , LaMotte Carole C. 
Published: January 2005

AbstractLight microscopical degeneration and ultrastructural alterations in the rat spinal dorsal horn were studied following either cutting of the sciatic nerve or rhizotomy at L4 and L5; survival time for both procedures was 3 weeks. Fink‐Heimer silver methods showed minimal degeneration of afferent central processes after sciatic section, and limited ultrastructural changes were present. Both rhizotomy and nerve section resulted in degenerating terminals. Most were swollen and electron lucent, with loss of vesicles; some electron‐dense terminals were present, particularly after rhizotomy. Both procedures also produced significant degeneration of postsynaptic dendrites and soma, evidenced by either increases in electron density, or loss of organelles and cavitation, or accumulation of osmiophilic floccular material. Glial processes frequently were expanded and extended to engulf single degenerating terminals and dendrites, or terminal‐dendrite units; in other cases glial tongues separated terminals from their postsynaptic dendrite. Glial processes often wrapped around degenerating profiles or groups of profiles in several layers, sometimes forming complex labyrinths. These results confirm past descriptions of pre‐ and postsynaptic changes resulting from peripheral nerve section, but newly reveal that dendritic destruction and increased glial activity are also significant following rhizotomy. Documentation of these changes is relevant for studies of reorganization following nerve and spinal cord damage, as well as providing an ultrastructural basis for evaluation of effects of neurotoxins that affect primary afferents, as described in a companion paper.
Autoradiographic studies of cerebellar histogenesis in the premetamorphic bullfrog tadpole: I. Generation of the external granular layer
Authors: Uray Nándor J. , Gona Amos G. , Hauser Kurt F. 
Published: January 2005

AbstractThis study examines the time of origin of cells in the external granular layer (EGL) in the frog cerebellum during early stages of development. Premetamorphic bullfrog tadpoles were given multiple intraperitoneal injections of 3H‐thymidine (10 m̈Ci/g body weight per injection) at developmental stages ranging from 4 weeks to 1 year and were killed at either 6 or 12 months of age. Autoradiograms were analyzed to determine the time when cells of the EGL were generated by an examination of the labeling pattern in the neuroepithelial cap where EGL cells were presumably formed and in the EGL into which they migrated.The developmental stage of the cerebellum in the 6‐month‐old tadpole was essentially the same as that of the 12‐month‐old animal except for an increased size in the older tadpole. The cerebellum in both age groups contained a distinct neuroepithelial cap and an EGL, which was somewhat better formed in the 12‐month‐old tadpole. Some heavily labeled cells were found in the neuroepithelial caps of 6‐month‐old tadpoles from injection times of 6 weeks to 6 months. In the cerebella of 12‐month‐old tadpoles, however, heavily labeled cells were found in the neuroepithelial cap only with the injection time of 12 months; with injection times from 7 to 11 months, the cells were labeled lightly. Labeled EGL cells were found in the cerebella of 6‐month‐old tadpoles from an injection time of 6 weeks on; with injection times from 10 weeks to 6 months some EGL cells contained heavy amounts of label. In the cerebella of 12‐month‐old tadpoles, labeling of EGL cells was not detectable with injection times of 7–9 months; they contained light to medium labeling with injection times of 10 and 11 months and heavy labeling when injected at 12 months. These results indicate that EGL cells are generated continuously in premetamorphic tadpoles from the age of 6 weeks to 12 months. Furthermore, these results suggest that the rate of EGL cell formation is faster during the second half‐year of development than during the first.
Somatostatin‐like immunoreactive material in the rabbit retina: Immunohistochemical staining using monoclonal antibodies
Authors: Sagar Stephen M. 
Published: January 2005

AbstractTwo mouse monoclonal antibodies to somatostatin‐14 were used with avidin‐biotin‐peroxidase immunohistochemical technique to examine the rabbit retina. In agreement with a previous study using a polyclonal anti‐serum, a sparse population (about 1,000 per retina) of neurons in the ganglion cell layer are immunoreactive for somatostatin; the vast majority of these cells are inferior to the myelinated fiber bundle. In addition, the monoclonal antibodies disclose a second neuronal population that forms a circumferential band of immunoreactive neurons around the extreme periphery of the retina. The cells in the body of the inferior retina have dendrites that ramify in the inner plexiform layer. Both the circumferential band of cells and the cells in the body of the inferior retina give off axonlike processes that run in the inner plexiform layer and do not enter the optic nerve. These long, straight varicose fibers form a meshwork that covers the entire retina. The superior retina, which contains only rare immunoreactive cell bodies, has a plexus of stained fibers comparable to that of the inferior retina.The circumferential band of cells is relatively resistant to the neurotoxin kainic acid, explaining a previously reported observation that this toxin depletes only about 50% of the content of somatostatin‐like immunoreactivity from the rabbit retina. Moreover, the somatostatin immunoreactive neurons are not labeled by the intraocular injection of the fluorescent dye DAPI, which labels the cholinergic displaced amacrine cells of the rabbit retina. These observations imply that somatostatin‐like immunoreactivity is localized to two populations of associational ganglion cells, neurons with cell bodies in the ganglion cell layer, the axons of which remain within the retina.
Volumes of the components of the hippocampus in the aging F344 rat
Authors: Coleman Paul D. , Flood Dorothy G. , West Mark J. 
Published: January 2005

AbstractMuch of the recent data on cells, synapses, and other structures in the dentate gyrus and hippocampus as a function of age are packing density or volume fraction data. In order to estimate total numbers, volumes, or surface areas of cells, synapses, vessels, etc., as a function of age, the total volumes of the subregions of the dentate gyrus and hippocampus must be known. The volumes of these subregions, visualized with the Timm stain, have been determined in 24 F344 rats from 4 to 37 months of age. Volumes of the various structures showed age‐related increases which were statistically significant for the perforant path zone of the dentate gyrus molecular layer, as well as the total molecular layer, the hilus, and regio inferior and total mossy fiber systems. If the 4‐month age group is eliminated from consideration, only the ratio of the volume of the mossy fiber zones to the volume of the perforant path zones of the dentate molecular layer increases significantly with age. Our general finding of lack of volumetric reorganization of the subdivisions of the hippocampal region between 12 and 37 months suggests that studies of the packing densities of structures in most of these zones may be considered comparable across ages, assuming comparability of sampling regions.
Somatotopic organization of the primary sensory trigeminal neurons in the hagfish, Eptatretus burgeri
Authors: Nishizawa Hideo , Kishida Reiji , Kadota Tetsuo , Goris Richard C. 
Published: January 2005

AbstractPrimary sensory trigeminal projections were investigated in the hagfish following application of horseradish peroxidase (HRP) to the sensory branches. In our control preparations we were able to distinguish five sensory ganglia and their respective nerves. HRP application confirmed the almost exclusive relation of each of these nerves to their respective ganglia, with very little overlap. In normal frontal sections of the medulla oblongata, five columns of fibers surrounded by neuronal cell bodies could be clearly distinguished, but the number is probably fortuitous, for there was no one‐on‐one relationship with the five trigeminal ganglia. From their peripheral connections, we surmised that columns 1 and 3 handle general cutaneous sensation, columns 2, 4, and 5 handle taste sensation, and column 5 handles general mucous cutaneous sensation conveyed by utricular ganglion cells. Dorsally located columns received projections from nerves with dorsal peripheral connections, and more ventrally located columns received projections from nerves with ventral peripheral connections. This relation is the reverse of that seen in other vertebrates.
Neuronal death and synapse elimination in the olivocerebellar system: III. Cell counts in the inferior olive of developing rats X‐irradiated from birth
Authors: Geoffroy Brigitte , Shojaeian Hadi , Delhaye‐Bouchaud Nicole , Mariani Jean 
Published: January 2005

AbstractThe change with age of cell number in the developing inferior olivary nucleus (ION) of the normal rat, compared to the time course of the regression of the polyneuronal innervation of Purkinje cells by olivary axons (i.e., the climbing fibers), suggests that the involution of the redundant olivocerebellar contacts is caused by a reduction of axonal branching rather than by degeneration of the parent cells, this being also suggested by the normal size of the olivary population in adult rodents whose Purkinje cells retain polyneuronal innervation. However, the similar size of the adult ION population does not necessarily imply that the developmental history is the same in normal and multiply innervated adult rodents. Therefore, cell counts were performed in developing rats which had been repeatedly X‐irradiated from birth until postnatal day 14 and which retained polyneuronal innervation. The results show that, although less marked than during normal development, the evolution of the ION population is also characterized by a phase of cell loss followed by a slow increase. However, the number of cells in X‐irradiated rats is higher than in their controls from birth to postnatal day 15 but becomes identical at 20 days and later. These data confirm that cell death in the ION does not play a major role in the shaping of olivocerebellar connections.
Immunohistochemical localization of serotonin and choline acetyltransferase in sensory neurones of the locust
Authors: Lutz E. M. , Tyrer N. M. 
Published: January 2005

AbstractSensory neuronal cell bodies in the leg of locust, Schistocerca gregaria, were visualized with antibodies to locust choline acetyltransferase and with antibodies to serotonin by the avidin‐biotin peroxidase technique. Two groups of sensory cells react with the antibody to choline acetyltransferase: One group is associated with external mechanoreceptors (i.e., hair‐plate hairs and campaniform sensilla) and the other with internal proprioceptors (i.e., chordotonal organs and multiterminal receptors). Sensory cells which react with the antibody to serotonin are associated only with internal proprioceptors being found in both chordotonal organs and multiterminal receptors. In the metathoracic femoral chordotonal organ indirect evidence suggests that some sensory cells are reactive to both antibodies. Some multiterminal receptors react with anti‐choline‐acetyltransferase, while others react with antiserotonin. These results support the conclusion that most insect sensory neurones are cholinergic but some are serotoninergic.
Brainstem afferents to the magnocellular basal forebrain studied by axonal transport, immunohistochemistry, and electrophysiology in the rat
Authors: Semba K. , Reiner P. B. , McGeer E. G. , Fibiger H. C. 
Published: January 2005

AbstractBrainstem afferents to the magnocellular basal forebrain were studied by using tract tracing, immunohistochemistry and extracellular recordings in the rat. WGA‐HRP injections into the horizontal limb of the diagonal band (HDB) and the magnocellular preoptic area (MgPA) retrogradely labelled many neurons in the pedunculopontine and laterodorsal tegmental nuclei, dorsal raphe nucleus, and ventral tegmental area. Areas with moderate numbers of retrogradely labelled neurons included the median raphe nucleus, and area lateral to the medial longitudinal fasciculus in the pons, the locus ceruleus, and the medial parabrachial nucleus. A few labelled neurons were seen in the substantia nigra pars compacta, mesencephalic and pontine reticular formation, a midline area in the pontine central gray, lateral parabrachial nucleus, raphe magnus, prepositus hypoglossal nucleus, nucleus of the solitary tract, and ventrolateral medulla. A similar but not identical distribution of labelled neurons was seen following WGA‐HRP injections into the nucleus basalis magnocellularis.The possible neurotransmitter content of some of these afferents to the HDB/MgPA was examined by combining retrograde Fluoro‐Gold labelling and immunofluorescence. In the mesopontine tegmentum, many retrogradely labelled neurons were immunoreactive for choline acetyltransferase. In the dorsal raphe nucleus, some retrogradely labelled neurons were positive for serotonin and some for tyrosine hydroxylase (TH); however, the majority of retrogradely labelled neurons in this region were not immunoreactive for either marker. The ventral tegmental area, substantia nigra pars compacta, and locus ceruleus contained retrogradely labelled neurons which were also immunoreactive for TH. Of the retrogradely labelled neurons occasionally observed in the nucleus of the solitary tract, prepositus hypoglossal nucleus, and ventrolateral medulla, some were immunoreactive for either TH or phenylethanolamine‐N‐methyltransferase.To characterize functionally some of these brainstem afferents, extracellular recordings were made from antidromically identified cortically projecting neurons, mostly located in the HDB and MgPA. In agreement with most previous studies, about half (48%) of these neurons were spontaneously active. Electrical stimulation in the vicinity of the pedunculopontine tegmerital and dorsal raphe nuclei elicited either excitatory or inhibitory responses in 21% (13/62) of the cortically projecting neurons.These findings indicate that neurons in the magnocellular basal fore‐brain receive afferents from widely distributed brainstem neurons that contain acetylcholine, serotonin, dopamine, noradrenaline, adrenaline, and some unknown neurotransmitters. Through their actions on magnocellular basal forebrain neurons, these brainstem neurons may indirectly regulate the activity of neurons throughout the cerebral cortex.