bluuebunny/crossref_metadata_2025_split huggingface dataset:
Müller cells in vascular and avascular retinae: A survey of seven mammals
Authors: Dreher Zofia , Robinson Stephen R. , Distler Claudia 
Published: May 2005

AbstractEight monoclonal antibodies were used to label Müller cells in four mammals that have vascular retinae (cats, dogs, humans, and rats) and in three with avascular retinae (echidnas, guinea pigs, and rabbits). Müller cells were found to have a fairly uniform retinal distribution in seven species, with a mean density of 8,000–13,000 cells mm−2. Müller cells in avascular retinae differ from their vascular counterparts in four respects. First, they are shorter than those in vascular retinae. This difference is mainly due to a reduction in the thickness of the outer nuclear layer. Second, the trunks of Müller cells in avascular retinae tend to be thicker, although those in echidnas are an exception to this trend. Third, Müller cell rootlets in avascular retinae follow a more tortuous course than those in vascular retinae, reflecting the fact that photoreceptor nuclei in the two types of retina have different shapes and stacking patterns. Fourth, due to a reduction in the density of photoreceptors in avascular retinae, there are fewer neurones per Müller cell.Although these four features may enable Müller cells to assist the nutrition of neurones in the inner layers of avascular retinae, they are unlikely to be morphological specializations that have evolved for that purpose. Rather, these features appear to be a direct consequence of the fact that avascular retinae are thinner and have a differently organised outer nuclear layer. These features aside, Müller cells in avascular retinae closely resemble their counterparts in vascular retinae. © 1992 Wiley‐Liss, Inc.
Prenatal formation of the normal mouse corpus callosum: A quantitative study with carbocyanine dyes
Authors: Ozaki Hiroki S. , Wahlsten Douglas 
Published: May 2005

AbstractJudgment of abnormalities in fetal cortical axon development is more sensitive when a good standard of normal ontogeny is established. The recent availability of postmortem tract tracing methods has greatly improved the observation of axon extension and growth cone morphology in mouse fetuses, which allows much stronger statements about the timing of crucial steps in the formation of the corpus callosum in particular. The first outgrowth and crossing of midplane by axons of the corpus callosum (CC) were examined in 153 normal mouse embryos and fetuses of the hybrid cross B6D2F2/J with carbocyanine dyes applied to brains fixed by perfusion. In most brains a crystal of DiI was inserted into either frontal, parietal, temporal, or occipital cortex in one hemisphere, and a crystal of DiA was placed into a different site in the opposite hemisphere. Although dye diffusion obscured the emergence of axons, linear regression analysis revealed that the first callosal axons emerged from their cortical cells of origin at about 0.4 g body weight or 15.5 days after conception for all four sites. Subsequent axon growth rate was substantially faster for those from frontal cortex (3.2 mm/day) than occipital cortex (1.8 mm/day). Axons from frontal cortex crossed the cerebral midplane first (0.69 g, E16.3), followed by those from parietal (0.74 g), temporal (0.77 g) and occipital cortex (0.92 g, E16.9). Prior to crossing midplane, the pioneering CC axons were usually 200 μm or less in advance of the main bundle, but when they crossed midplane and encountered CC axons growing from homotopic sites in the opposite hemisphere, the pioneering axons were often 0.5 to 2.5 mm ahead of the main bundle. Growth cones were usually large and complex until they had crossed midplane and were thereafter smaller with simple and flat morphologies. The topography of axons in the CC at midplane was organized according to cortical region of origin from the very beginning, when the CC was only a small cap over the hippocampal commissure and dorsal septum. The quantitative results provide a convenient, standard for normal callosal development in mice and should facilitate comparative studies. © 1992 Wiley‐Liss, Inc.
Time of origin of cortico‐collicular projection neurons in the rat visual cortex
Authors: Contamina P. , Boada E. 
Published: May 2005

AbstractThe time of origin and the radial gradient of neurogenesis of cortico‐collicular neurons have been studied in the rat visual area 17. We used a combined technique for the histochemical detection of the retrogradely transported horseradish peroxidase from the superior colliculus and the autoradiographic detection of the [3H]‐thymidine administered during the gestational period. The cortico‐collicular neurons of visual area 17 are located in layer V and are generated on gestational day (GD) 15 (59.78%), GD 16 (36.21%), and GD 17 (4.01%). This finding reveals that, for the cortico‐collicular neuronal population, the birth date is well‐correlated with the laminar position in the adult animal. To see whether the cortico‐collicular neurons located at various radial levels of layer V are generated concurrently, or whether they follow an “insideout” pattern of positioning, we divided layer V into three (upper, middle and lower) sublaminae. Most cortico‐collicular neurons located in the lower two‐thirds of layer V are generated on GD 15 (65%), whereas the neurons located in the upper third of the layer are generated both on GD 15 and GD 16 in almost equal proportions (52.53% and 44.39%, respectively). © 1992 Wiley‐Liss, Inc.
Projections from the lateral nucleus to the basal nucleus of the amygdala: A light and electron microscopic PHA‐L study in the rat
Authors: Stefanacci Lisa , Farb Claudia R. , Pitkänen Asla , Go Gene , Ledoux Joseph E. , Amaral David G. 
Published: May 2005

AbstractA recent study, carried out in the monkey brain demonstrated a hitherto undescribed projection from the lateral to the basal nucleus of the amygdaloid complex. In the present study, we used light and electron microscopic techniques to determine whether a similar connection exists in the rat brain and to define what type(s) of synaptic contacts are produced by fibers of this projection. Injections of the lectin tracer Phaseolus vulgaris leucoagglutinin (PHA‐L) were placed into several levels of the lateral nucleus and the distribution of fibers in the basal (basolateral) nucleus was evaluated. All lateral nucleus injections resulted in labeled fibers in the basal nucleus, though the density and distribution of labeled fibers depended on the position of the injection site within the lateral nucleus. In general, the heaviest labeling of the basal nucleus was observed after injections at midrostrocaudal levels of the lateral nucleus, especially when the injection was located ventrally. Fibers originating from cells labeled by these injections were observed throughout much of the rostrocaudal extent of the basal nucleus. Rostrally situated injections resulted in substantially lower levels of labeled fibers in the basal nucleus. Injections placed caudally in the lateral nucleus resulted in light to medium levels of labeled fibers in the basal nucleus; the terminal field in these cases did not extend as far rostrally as after the rostral and midlevel injections. Electron microscopic analysis of PHA‐L labeled fibers revealed that they contributed synapses to the basal nucleus. The majority of PHA‐L labeled terminals formed asymmetric contacts on dendritic spines or shafts; a smaller number of PHA‐L labeled terminals formed symmetrical synapses. © 1992 Wiley‐Liss, Inc.
Contractile proteins in the hyaline cells of the chicken cochlea
Authors: Cotanche Douglas A. , Henson Miriam M. , Henson O. W. 
Published: May 2005

AbstractHyaline cells are a single layer of epithelial cells found at the inferior edge of the sensory epithelium in the chick cochlea. They rest directly above a specialized region of the basilar membrane at a point where it connects to the fibrocartilaginous skeleton of the cochlear duct. The basal cytoplasm of the hyaline cells contains a bundle of linearly aligned actin filaments that resemble stress fibers in their organization. The actin filaments are anchored in the basal plasma membranes of the cells, which are, in turn, associated with the underlying basal lamina and the extracellular matrix of the basilar membrane. We have used a combination of transmission electron microscopy, differential‐interference‐contrast and epifluorescence light microscopy, and confocal laser scanning microscopy to study the composition and organization of these actin bundles within the hyaline cells. The bundles are arranged into triangular wedges that are oriented radially across the basilar membrane. Each cell contains one or two actin wedges. Adjacent cells can have them aligned in opposite directions so that in a whole‐mount surface preparation they appear as interdigitations. Immunofluorescent staining of the hyaline cells has shown that smooth muscle myosin and α‐actinin are co‐localized to the actin bundles. Smooth muscle myosin is also found throughout the cytoplasm of the cells. The fact that hyaline cells in the chick cochlea are contacted by efferent nerve fibers suggests that these cells may regulate tension on the basilar membrane via the specialized bundle of actin filaments.
Projections from the commissural subnucleus of the nucleus of the solitary tract: An anterograde tracing study in the cat
Authors: Otake Kazuyoshi , Ezure Kazuhisa , Lipski Janusz , Wongshe Richard B. 
Published: May 2005

AbstractThe commissural subnucleus (COM) of the nucleus of the solitary tract (NTS) is known to receive primary afferents from the lungs and other viscera innervated by the vagus nerve, and thus to participate in central autonomic and respiratory control. The aim of the present study was to identify the areas of terminal arborizations of COM neurons in order to examine brainstem sites which may be involved in reflex responses mediated by these neurons. The projections were studied in cats, using biocytin as an anterograde tracer. Labeled fibers and terminal boutons were visualized by horseradish‐peroxidase histochemistry, 2–3 days after microinjection of the tracers into the COM 1–2 mm caudal to the obex. Labeled axons were examined in the brainstem from the rostral pons to the caudal medulla and were found bilaterally, with an ipsilateral predominance, mainly in the following regions: (1) The dorsolateral rostral pons. Terminal boutons were observed in the lateral and medial parabrachial nuclei, Kölliker‐Fuse nucleus, and around the mesencephalic trigeminal tract. This area corresponds to the pontine respiratory group also known as the “pneumotaxic center.” (2) The pontine area dorsolateral to the superior olivary nucleus. This region contains the A5 noradrenergic cell group; (3) Near the ventral surface, below the facial nucleus. This area overlaps with the ‘retrotrapezoid nucleus.’ (4) Respiration‐related areas of the medulla, including the dorsal and ventral respiratory groups, and the Bötzinger complex. (5) The dorsal motor nucleus of the vagus.These results suggest that the COM is involved in reflex arcs, which have both respiratory functions and autonomic functions. The pathway to the dorsolateral pons, which has been identified in our recent electrophysiological study is likely to play a role in mediating respiratory responses from pulmonary rapidly adapting receptors. Other pathways may represent additional projections from second‐order neurons receiving input from this group of lung receptors, or projections from as yet unidentified neurons that relay information from different afferents terminating in the COM.
Corticotectal projections in the cat: Anterograde transport studies of twenty‐five cortical areas
Authors: Harting John K. , Updyke Bruce V. , van Lieshout David P. 
Published: May 2005

AbstractRetrograde transport studies have shown that widespread areas of the cerebral cortex project upon the superior colliculus. In order to explore the organization of these extensive projections, the anterograde autoradiographic method has been used to reveal the distribution and pattern of corticotectal projections arising from 25 cortical areas. In the majority of experiments, electrophysiological recording methods were used to characterize the visual representation and cortical area prior to injection of the tracer.Our findings reveal that seventeen of the 25 cortical areas project upon some portion of the superficial layers (stratum zonale, stratum griseum superficiale, and stratum opticum, SO). These cortical regions include areas 17, 18, 19, 20a, 20b, 21a, 21b, posterior suprasylvian area (PS), ventral lateral suprasylvian area (VLS), posteromedial lateral suprasylvian area (PMLS), anteromedial lateral suprasylvian area (AMLS), anterolateral lateral suprasylvian area (ALLS), posterolateral lateral suprasylvian area (PLLS), dorsolateral lateral suprasyvian area (DLS), periauditory cortex, cingulate cortex, and the visual portion of the anterior ectosylvian sulcus. While some of these corticotectal projections target all superficial laminae and sublaminae, others are more discretely organized in their laminar‐sublaminar distribution. Only the corticotectal projections arising from areas 17 and 18 are exclusively related to the superficial layers. The remaining 15 pathways innervate both the superficial and intermediate and/or deep layers.The large intermediate gray layer (stratum griseum intermedium; SGI) receives projections from almost every cortical area; only areas 17 and 18 do not project ventral to SO. All corticotectal projections to SGI vary in their sublaminar distribution and in their specific pattern of termination. The majority of these projections are periodic, or patchy, and there are elaborate (double tier, bridges, or streamers) modes of distribution. We have attempted to place these findings into a conceptual framework that emphasizes that the SGI consists of sensory and motor domains, both of which contain a mosaic of connectionally distinct afferent compartments (Illing and Graybiel, '85, Neuroscience 14:455–482; Harting and Van Lieshout, '91, J. Comp. Neurol. 305:543–558).Corticotectal projections to the layers ventral to SGI, (stratum album intermediale, stratum griseum profundum, and stratum album profundum) arise from thirteen cortical areas. While an organizational plan of these deeper projections is not readily apparent, the distribution of several corticotectal inputs reveals some connectional parcellation.
Further study of the aberrant optic nerve projection to olfactory cortex
Authors: Scalia Frank 
Published: May 2005

AbstractWhen implanted into the cerebral hemisphere, the regenerating optic nerve of the adult frog (Rana pipiens) forms a well‐defined terminal field in the pars ventralis of the lateral (olfactory) cortex, and sometimes expands medially into the postolfactory eminence. These adjacent areas receive their normal input from the main olfactory bulb. The aberrant projection extends caudally toward the core neuropil of the medial amygdaloid nucleus, which receives its normal input from the accessory olfactory bulb, but does not enter this vomeronasal sector of the amygdala. The present study tests whether: (1) optic fibers would innervate the vomeronasal amygdala after surgical ablation of the accessory olfactory bulb, (2) the projection would transpose into adjacent cortex after olfactory cortex lesions, and (3) the projection would overflow into adjacent areas after being amplified by hemisection at the di‐telencephalic junction (to minimize escape of fibers into the diencephalon). The retinal projection always terminated in the olfactory cortex when this area was intact, or in spared fragments of it after radical cortical lesions, but never entered the vomeronasal amygdala in any specimen, as studied by autoradiographic and horseradish peroxidase tracing techniques. With forebrain hemisection, the cortical terminal field increased in thickness but remained confined to the olfactory area. However, the interruption of the lateral forebrain bundle induced a new projection to the striatum in a region neighboring but separate from the olfactory cortical field. These findings support the hypothesis that retinal fibers have a specific affinity for primary olfactory cortex that is not normally allowed expression in development. Retinal fibers may also have a latent affinity for the striatum that is unmasked after deafferentation.
Afferents to the oculomotor nucleus in the goldfish (Carassius auratus) as revealed by retrograde labeling with horseradish peroxidase
Authors: Torres B. , Pastor A. M. , Cabrera B. , Salas C. , Delgado‐García J. M. 
Published: May 2005

AbstractThe goal of this work was to compare the distribution and morphology of neurons projecting to the oculomotor nucleus in goldfish with those previously described in other vertebrate groups. Afferent neurons were revealed by retrograde labeling with horseradish peroxidase. The tracer was electrophoretically injected into the oculomotor nucleus. The location of the injection site was determined by the antidromic field potential elicited in the oculomotor nucleus by electrical stimulation of the oculomotor nerve. Labeled axons whose trajectories could be reconstructed were restricted to the medial longitudinal fasciculus. In order of quantitative importance, the afferent areas to the oculomotor nucleus were: (1) the ipsilateral anterior nucleus and the contralateral tangential and descending nuclei of the octaval column. Furthermore, a few labeled cells were found dorsomedially to the caudal pole of the unlabeled anterior octaval nucleus; (2) the contralateral abducens nucleus. The labeled internuclear neurons were arranged in two groups within and 500 μm behind the caudal subdivision of the abducens nucleus; (3) a few labeled cells were observed in the rhombencephalic reticular formation near the abducens nucleus, most of which were contralateral to the injection site. Specifically, stained cells were found in the caudal pole of the superior reticular nucleus, throughout the medial reticular nucleus and in the rostral area of the inferior reticular nucleus; (4) eurydendroid cells of the cerebellum, located close to the contralateral eminentia granularis pars lateralis, were also labeled; and (5) a small and primarily ipsilateral group of labeled cells was located at the mesencephalic nucleus of the medial longitudinal fasciculus.The similarity in the structures projecting to the oculomotor nucleus in goldfish to those in other vertebrates suggests that the neural network involved in the oculomotor system is quite conservative throughout phylogeny. Nevertheless, in goldfish these projections appeared with some specific peculiarities, such as the cerebellar and mesencephalic afferents to the oculomotor nucleus.
Immunohistochemical distribution and biological activity of pituitary adenylate cyclase‐activating polypeptide (PACAP) in the central nervous system of the frog Rana ridibunda
Authors: Yon Laurent , Feuilloley Marc , Chartrel Nicolas , Arimura Akira , Conlon J. Michael , Fournier Alain , Vaudry Hubert 
Published: May 2005

AbstractThe primary structure of frog pituitary adenylate cyclase‐activating polypeptide (PACAP) has recently been determined and the results show that the sequence of PACAP has been highly conserved during evolution. In particular, the structure of the 1–27 fragment of PACAP is identical in frog and mammals. Using an antiserum raised against PACAP27, we have investigated the distribution of PACAP‐containing neurons in the central nervous system of the frog Rana ridibunda by the immunofluorescence technique. The main populations of immunoreactive perikarya were located in the medial and ventral diencephalon, i.e., the preoptic nucleus, the ventral and dorsal infundibular nuclei, the nucleus posterocentralis thalami, and the ventral and ventrolateral areas of the thalamus. In the telencephalon, sparse cell bodies were found in the nucleus accumbens septi, the amygdala, the pallial commissure, and the bed nucleus of the pallial commissure. In the hindbrain, the torus semicircularis, the nucleus profundus and the nucleus anteroventralis tegmenti of the mesencephalon also contained populations of PACAP‐immunoreactive perikarya. Beaded nerve fibers were observed throughout the brain. Occasionally they formed bundles, e.g., from the ventral infundibulum to the external vascular layer of the median eminence, from the central thalamus to the optic tectum, and rostrocaudally, from the nucleus accumbens septi to the nucleus entopeduncularis. Other areas, such as the interpeduncular nucleus, the nucleus isthmi and the roots of cranial nerves V and VIII in the medulla oblongata, were also densely innervated. The adenylate cyclase‐stimulating activity of PACAP was tested by using a static incubation technique for hypothalamic slices. Synthetic PACAP27 (lO−10 to 3 · 10−6 M) induced a dose‐dependent stimulation of cAMP production. The half‐maximum effective dose (ED50) of PACAP27was3.5 · 10−7 M.Taken together, these results provide the first evidence for the presence of PACAP in the central nervous system of nonmammalian vertebrates. The discrete localization of PACAP immunoreactivity in the brain and the adenylate cyclase‐stimulating activity of PACAP27 on frog hypothalamic slices suggest that PACAP acts as a neurotransmitter or neuromodulator in the brain of amphibians.
Projections to the medial superior olive from the medial and lateral nuclei of the trapezoid body in rodents and bats
Authors: Kuwabara N. , Zook J. M. 
Published: May 2005

AbstractIn this study we present direct evidence of axonal projections from both the medial and lateral nuclei of the trapezoid body to the medial superior olive. Projections were traced by intracellularly labeling cells and axons in a tissue slice preparation of two rodent species, Mus musculus and Meriones unguiculatus and two bat species, Eptesicus fuscus and Pteronotus parnellii.The main axon of most principal cells in the medial nucleus of the trapezoid body gives off one or more collateral branches which arborize within the medial superior olive. These collateral axons form small bouton‐like swellings which primarily contact somata within the central cell column in the medial superior olive. Likewise, labeled elongate and multipolar cells of the lateral nucleus of the trapezoid body send axons to both the medial and lateral superior olives. These axons also form perisomatic contacts in both target nuclei.These two sets of projections may relay ascending input to the medial superior olive and the lateral superior olive; the medial nucleus of the trapezoid body is known to relay input from the contralateral ventral cochlear nucleus, and the lateral nucleus of the trapezoid body may relay input from the ipsilateral ventral cochlear nucleus. These projections offer two routes for indirect, possibly inhibitory input to reach the medial superior olive from both cochlear nuclei. These indirect, inhibitory pathways may parallel the direct excitatory projections the medial superior olive receives from each cochlear nucleus.