bluuebunny/crossref_metadata_2025_split huggingface dataset:
An analysis of the retinal afferents to the cat's medial interlaminar nucleus and to its rostral thalamic extension, the “geniculate wing”
Authors: Guillery R. W. , Geisert E. E. , Polley E. H. , Mason C. A. 
Published: January 2005

AbstractThe retinal afferents to the medial interlaminar nucleus and to its rostro‐dorsal extension at the edge of the pulvinar have been studied in cats by fiber degeneration and autoradiographic methods. Fiber degeneration following section of one optic nerve shows two distinct retinal inputs: One is coarse‐fibered and goes to the medial interlaminar nucleus itself; the second, which is fine‐fibered, goes to the rostral and medial borders of the medial interlaminar nucleus and continues into the pulvinar. The regions in receipt of these fine fibers have been called the “geniculate wing”.The topography of retinal representations and the degree of binocular overlap within the medial interlaminar nucleus and the wing have been studied by combining intraocular injections of 3H proline with local lesions of the injected eye, or with removal of the non‐injected eye. In the medial interlaminar nucleus three distinct laminae are recognizable and are particularly clearly shown in horizontal sections. Rostrally and medially, lamina 1 maps the contralateral nasal retina as a mirror reversal of lamina A. Posterior and lateral to this, lamina 2 maps the ipsilateral temporal retina as a mirror reversal of lamina A1. Lamina 3 lies closest to the optic tract and receives crossed afferents from the temporal retina. In this lamina, which is the smallest, vertical retinal dimensions map as in the other layers, but we were unable to determine the mapping of the horizontal dimensions.In the geniculate wing, as in the other geniculate layers, vertical lines of the visual field are mapped as corresponding vertical diencephalic dimensions; horizontal retinal dimensions are mapped as horizontal lines in the wing, with central retinal areas represented furthest from the optic tract. In the geniculate wing the contralateral nasal and ipsilateral temporal retina are mapped with considerable binocular overlap. The crossed temporal retina has no demonstrable representation in the wing.
[14C] deoxyglucose mapping of first‐order projections activated by stimulation of lateral hypothalamic sites eliciting gnawing, eating, and drinking in rats
Authors: Roberts Warren W. 
Published: January 2005

AbstractRats having hypothalamic electrodes that elicited gnawing, eating; and drinking in free‐moving tests received intermittent electrical stimulation for 45 min following i.v. injection of [14C] deoxyglucose. Autoradiographs of regional brain glucose utilization were made by the method of Sokoloff et al. ('77). To maximize the detectability of first‐order neuronal effects and minimize potentially complex transsynaptic effects, baseline metabolism and synaptic transmission were reduced by light barbiturate anesthesia. Laterally asymmetrical increases in glucose utilization indicative of elicited activity were largely coterminous with the known projections of the lateral hypothalamus and some projections of adjoining areas, indication that most first‐order efferent were subthreshold. Although the majority of hypothalamic projections were similarly affected in control rats that received hypothalmic stimulation that elicited other responses, a number were activated significantly less than in the rats whose electrodes induced gnawing, eating, and drinking. Chief among these areas was a continuous descending pathway from the ventral tegmental area through the lateral tegmentum to the cuneiform and parabrachial nuclei. Smaller and/or less reliable increases above controls were found in the dorsomedial caudate‐putamen, the posterolateral zona incerta, the anterior lateral central gray, the caudal linear nucleus, the laterodorsal tegmental nucleus, the pontine tegmental nucleus, and a previously undescribed pathway lying medially between the pontine medial lemniscus and cerebral peduncle. These areas, especially the lateral tegmental and parabrachial zone, are the most likely candidates of the pathways and/or destinations of the directly excited efferents or fibers of passage that constitute the first link in the elicitation of gnawing, eating, and drinking by lateral hypothalamic stimulation. Since self‐stimulation and exploratory activity were elicited by control as well as experimental electrodes, they are probably dependent of other projections among those affected similarly in both groups.
The cytoarchitecture, cytology, and synaptic organization of the basilar pontine nuclei in the rat. II. Electron microscopic studies
Authors: Mihailoff Gregory A. , McArdle Craig B. 
Published: January 2005

AbstractThe basilar pontine gray in adult rats was subjected to electron microscopic examination in order to characterize: (1) certain general cytologic features, (2) the principle categories of presynaptic profiles, and (3) the postysnaptic targets of the various categories of presynaptic boutons. General cytologic features included the presence of neuronal somata exhibiting either a smooth contoured nucleus and central nucleous or an irregularly contoured nucleus with numerous invaginations and an eccentric nucleolus. In addition, dendritic protrusions with variable morphology were apparent as well as a class of dendrites and somata with a curious dense, granular matrix. Four general types of presynaptic profiles were distinguished and were classified as: round vesicle boutons, elongate vesicle, pleomorphic vesicle, and dense core vesicle boutons. The category of round vesicle boutons formed asymmetric synaptic contacts and included three subtypes. One group contained vesicles with diameters of 25–35 nm, a second group contained larger (40–60 nm) round vesicles, and a third group of much larger boutons (2.5–6.8 μm) exhibited the smaller round vesicles. Another general category of presynaptic profile contained distinctly elongated synaptic vesicles, formed symmetrical active sites, and ranged in size from 0.4–1.7 μm. A third category of synaptic end‐strucutures was distinguished by the presence of pleomorphic synaptic vesicles and microtubules and exhibited a distinctive pale or lucent matrix, while the fourth type was characterized by a mixed population of clear and dense core vesicles. Analysis of the distribution of such bouton types over the surface of pontine neurons revealed that: somata and proximal dendrites were contacted by round, elongate, and dense core vesicle boutons; intermediate and distal dendrites received synapses from all categories of boutons including the large endings with smaller round vesicles, while dendritic spines were contacted by round vesicle boutons (large and small), the large boutons, and elongate vesicle boutons. Synapses were also observed to occur between two vesicle‐containing profiles. In such situations, pleomorphic vesicle boutons were found to be postsynaptic to either elongate vesicle boutons or small boutons with round vesicles and at the same time were presynaptic to a dendritic profile.
Two visual pathways to the telencephalon in the nurse shark (Ginglymostoma cirratum). I. Retinal projections
Authors: Luiten Paul G. M. 
Published: January 2005

AbstractThe central projections of the retina in the nurse shark were studied by anterograde transport of horseradish peroxidase and tritiated proline. With regard to efferent retinal fibres, both techniques gave completely identical results. Projections were found to pretectal area, dorsal thalamus, basal optic nucleus, and optic tectum, all at the contralateral side. The retinal target cells in the dorsal thalamus are restricted to the ventrolateral optic nucleus and the posterior optic nucleus. No evidence was found for an earlier‐reported projection to the lateral geniculate nucleus. The present findings show that the ventrolateral optic nucleus exhibits homological features of the dorsal lateral geniculate nucleus in other vertebrate groups, whereas the lateral geniculate nucleus of the nurse shark is much more comparable to the nucleus rotundus of teleosts and birds and would be more appropriately so named. The application of the HRP technique also allowed us to study afferents to the retina by retrograde transport of tracer. Retrogradely labeled cells were observed in the contralateral optic tectum and are apparently similar to those reported for teleosts and birds.
Connections of the corticomedial amygdala in the golden hamster. II. Efferents of the “olfactory amygdala”
Authors: Kevetter Golda A. , Winans Sarah S. 
Published: January 2005

AbstractThe anterior cortical (C1) and posterolateral cortical (C2) nuclei of the amygdala are designated the “olfactory amygdala” because they each receive direct projections from the main olfactory bulb. The efferents of these nuclei were traced after sterotaxic placement of 1—5 μCi tritiated proline in the corticomedial amygdala of male golden hamsters. Following survival times of 12, 24, or 48 hours, 20 μm frozen sections of the brains were processed for light microscopic autoradiography.Efferents from C2 terminate in layers II and III of the olfactory tubercle and in layer lb of pars ventralis and pars medialis of the anterior olfactory nucleus. Fibers from this nucleus also project to layers I and II of the infralimbic cortex and to the molecular layer of the agranular insular cortex. More posteriorly, fibers from C2 teminate in layer I of the dorsolateral entorhinal cortex, and in the endopiriform nucleus.From C1, efferent fibers travel in the stria terminalis and terminate in the precommissural bed nucleus of the stria terminalis and in the mediobasal hypothalamus. Efferents from C1 also innervate the molecular layer of C2, the amygdalo‐hippocampal area, and the adjacent piriform cortex.Neurons in both C1 and C2 project to the molecular layer of the medial amygdaloid nucleus and the posteromedial cortical nucleus of the amygdala, the plexiform layer of the ventral subiculum, and the molecular layer of the lateral entorhinal cortex.
The structural organization of the ventral posterolateral nucleus in the rat
Authors: McAlliser J. P. , Wells J. 
Published: January 2005

AbstractThe structural plan of the ventral posterolateral nucleus (VLP) in the rat was analyzed by using a variety of techniques to study the pattern of distribution of the ascending afferent fibers and the synaptology of the neuropil within this somatosensory relay nucleus. Golgi stains, Fink‐Heimer methods, HRP labeling methods, and electron microscopy were all used in the analysis.The neurons in VPL are aligned in rostrocaudal and dorsoventral rows that are roughly parallel to the curvature of the external medullary lamina (EML) and curve partially around the rostral pole of the ventral posteromedial nucleus (VPM). Golgi‐impregnated section reveal that the dendritic trees of the VPL neurons conform in general to the laminar pattern of VPL. Thick proximal dendrites extend about 25 μm from the cell bodies. Most proximal dendrites are aligned with the laminae of VPL but the distal dendrites spread over many laminae within VPL. The inputs from the dorsal column nuclei (DCN) end only on proximal dendrites as large, round‐vesicle terminals. About 20–25% of the small round‐vesicle terminals originate in the cerebral cortex and synapse only on the distal dendrites. The third type of synapse contains many flattened vesicles and is of unknown origin. No serial synapses or vesicle‐containing dendrites were observed. Input from the spinal cord projects to two segregated zones which are transitional between the ventral lateral nucleus (VL) and VPL rostrally and between the posterior thalamic complex (PO) and VPL caudally. Each transition zone contains neurons characteristic of both VPL and the adjacent region. Ascending afferent projections were demonstrated by the antegrade transport of HRP following injections into the ventral mesencephalon and by Fink‐Heimer stains of degeneration resulting from small lesions of the DCN. Both methods indicate that large‐caliber axons course parallel to each other and give off collaterals that diverge to widespread areas of the VPL. The widespread terminal fields that result do not conform to the laminar pattern of the nucleus. Small punctate lesions of DCN result in sparse degeneration that is also widespread in VPL. Structures which appear to be clusters of terminal arborizations of the ascending afferent input were also observed in VPL. These results suggest that somatotopy and modality separation in VPL may be determined either by intrinsic and/or corticothalamic morphological relationships and not by precise topographical ordering of sensory input.
The pontocerebellar system in the rat: An HRP study. II. Hemispheral components
Authors: Mihailoff G. A. , Burne R. A. , Azizi S. A. , Norell G. , Woodward D. J. 
Published: January 2005

AbstractThe projection of basilar pontine neurons to the cerebellar hemispheres was studied in pigmented rats by means of the retrograde transport of horseradish peroxidase. Injections of horseradish peroxidase were restricted to the lateral aspects of the lobulus simplex (11 cases), crus I (26 cases), crus II (23 cases), and paramedian lobule (18 cases). The main focus of labeled neurons following lobulus simplex injections of horseradish peroxidase was located in the ventral pons, at rostral levels. Interestingly, the majority of labeled cells were distributed ipsilateral to the injection site. After crus I injections, however, labeled neurons were most evident contralaterally, although labeled ipsilteral cells were conspicuous rostrally. The majority of labeled cells were characteristically distributed along the medial, ventral, and lateral perimeters of the pontine gray. This pattern of labeling contrasts with that in cases of crus II injections, in which the main focus of labeled somata occupied more central regions of medial and ventral portions of the pons. Similarly, the pattern of labeling following injections into the paramedian lobule largely avoided the medial and lateral perimeters of the pontine gray, while numerous labeled somata occupied the central region of the pons. In addition to the pontine regions described above, labeled cells were observed in various cases in the dorsal peduncular region, the lateral and dorsolateral areas, and the nuclear reticularis tegmenti pontis (NRTP) where three separate zones of labeling could be discerned in various cases.Several general organizational features were derived from these studies. Although specific quantitation procedures were not applied, the number of ipsilaterally labeled neurons was impressive in some cases, as was the mirror‐image location of certain ipsi‐ and contra‐lateral cell clusters. It was also noted that certain, similarly located clusters of labeled pontine neurons were present in cases in which injections were made into different cerebellar lobules, at least raising the possibility that some pontine neurons might give rise to divergent projections to multiple cerebellar locations. Moreover, it was evident that the location of certain clusters of labeled neurons was congruent with terminal zones of various pontine afferent systems, particularly those of the sensorimotor cortex. Combining the latter finding with the preceeding notion regarding pontocerebellar divergence suggests a mechanism by which sensorimotor information might be transmitted to several different cerebellar locations.
Spinothalamic projections in a lizard, Varanus exanthematicus: An HRP study
Authors: Hoogland Piet V. 
Published: January 2005

AbstractIn the present study HRP injections have been placed in various thalamic areas in order to investigate spinothalamic projections in the lizard Varanus exanthematicus. It appeared that the spinal cord projects to three different thalamic areas: nucleus dorsomedialis, nucleus ventrolateralis, and an area that includes both the nucleus dorsolateralis and nucleus intermediodorsalis. Spinal neurons projecting to nucleus dorsomedialis are localized bilaterally at the medial side of the dorsal horn. Following injections in nucleus ventrolateralis, labeled neurons were found bilaterally in area VII and VIII, whereas nucleus dorsolateralis and nucleus intermediodorsalis receive a bilateral input mainly from areas V and VI.
Morphology and number of neurons in two species of polychaetes
Authors: Hulsebosch C. E. , Bittner G. D. 
Published: January 2005

AbstractNeurons of the ventral nerve cord (VNC) in the polychaete species Clymenella torquata and Nereis virens were ultrastructurally distinguished from glial cells by the smaller diameter and elongated shape of glial nuclei in adult organisms. In contrast to neurons, ß‐glycogen‐like particles and densely packed microfilaments were found in glial cytoplasm. Using these and other criteria glials cells were distinguished from nerve cells in histologic preparations.All neuronal nuclei were counted in specified regions of the CNS of both polychaetes. In both species, the number of neuronal nuclei in various CNS regions remained constant in animals of very different body size. Since Clymenella has a set number of ganglia in the VNC and a set number of body segments, the total number of CNS neurons remains constant in adult members of this species. Since adult Nereis adds VNC ganglia in newly forming body segments, the total number of CNS neurons continuously increases, but the total number of CNS neurons in a ganglion does nto change after it is formed.
The organization of thalamic projections to the parietal cortex of the Virginia opossum
Authors: Donoghue John P. , Ebner Ford F. 
Published: January 2005

AbstractThe thalamic projections to somatic sensory‐motor (SSM) cortex and adjacent cortical areas of the Virginia opossum were studied using anterograde and retrograde axoplasmic transport techniques. Large injections of horseradish peroxidase and/or tritiated amino acids were made in the parietal cortex to identify all of the thalamic nuclei that are interconnected with this large cortical area. Very restricted injections were then made in physiologically identified subdivisions of SSM cortex, in the remaining posterior portion of parietal cortex, and in the anteriorly adjacent postorbital cortex.The results show that the parietal cortex is reciprocally connected with a number of thalamic nuclei. Different combinations of these thalamic areas project to specific subregions within the parietal field. All parts of the SSM cortex, which occupies the anterior four‐fifths of parietal cortex, receive input from the ventrobasal complex (VB), the ventrolateral complex (VL), the central intralaminar nucleus (CIN), the central lateral nucleus (CL), and the ventromedial nucleus (VM). We could detect no segregation of VL and VB inputs in any part of SSM cortex. Projections from all of these thalamic nuclei, except VM. show at least some degree of topographic organization. Anterior‐posterior strips of SSM cortex receive input from clusters of thalamic neurons that extend dorsoventrally and rostrocaudally through VB and VL. The posterior one‐fifth of the parietal cortex (the posterior parietal area) receives input from VL, the posterior nuclear complex, and the lateral complex, as well as input from CL, CIN, and VM. Postorbital cortex receives input mainly from intralaminar, midline, and medial thalamic nuclei. We conclude that the projection field of VB in the parietal cortex coincides precisely with the first somatic sensory area (SI) as defined by single unit studies (Pubols et al., '76). The VB projection field also delineates the area of the first motor (MI) representation. Thus, there is no separation of SI and MI cortex in the opossum. The posterior parietal area lies outside of SSM cortex and has thalamic connections similar to the posterior parts of parietal cortex in other mammals.
Widespread corticostriate projections from temporal cortex of the rhesus monkey
Authors: Van Hoesen Gary W. , Yeterian Edward H. , Lavizzo‐Mourey Risa 
Published: January 2005

AbstractThe corticostriate projections of temporal areas TA, TE, TF, TG, 35, and 28 were studied in the rhesus monkey with the use of autoradiography. Widespread projections were observed to rostral as well as caudal parts of the striatum for all areas except area 28. For example, areas TA and TG have sizable projections to the medial or periventricular part of the head of the caudate nucleus, as well as to the medial part of the tail of this structure and the dorsally adjacent putamen. Areas TE and TF also were observed to send strong projections to the head of the caudate nucleus. In addition, they project to the rostral putamen. Both have projections to the tail of the caudate nucleus and caudal putamen.The widespread distribution of temporostriate axons to the rostral striatum suggests strongly that previous silver impregnation studies have not only underestimated the strength of the temporal cortical contribution to the corticostriate system, but also failed to identify the major projection zone of temporostriate axon terminals. For example, while all temporal cortical areas contribute projections to an organized topography in the tail of the caudate nucleus and the ventrocaudal putamen, they were observed consistently to have larger projections to the head of the caudate nucleus and rostral putamen.These results add to a growing body of evidence which demonstrates the existence of widespread nonmotor cortical input to the basal ganglia, and an organization of this input far greater in complexity than that demonstrated by earlier suppressive silver impregnation methods.
Matching populations of amacrine cells in the inner nuclear and ganglion cell layers of the rabbit retina
Authors: Vaney David I. , Peichl Leo , Boycott B. B. 
Published: January 2005

AbstractIn rabbit retina, neurofibrillar methods stain two populations of amacrines whose cell bodies are located on either side of the inner plexiform layer: on in the ganglion cell layer and the other at the inner margin of the inner nuclear layer. The stained amacrines in the ganglion cell layer have the distinctive cytology of ‘coronate’ amacrines described from Nissl‐stained retina (Vaney, 1980a) and account for about 85% of the displaced amacrines in the rabbit retina. The coronate amacrines have a streak topography similar to that of the ganglion cells; they comprise about 32% of the neurons in the ganglion cell layer although their proportion increases with eccentricity from the visual streak. The cytology of the neurofibrillar stained amacrines in the inner nuclear layer resembles that of the displaced amacrines and their densities are almost equal. The cell bodies of the stained amacrines are smaller than those of the displaced amacrines but larger than most others in the inner nuclear layer; they account for some 2% of the neurons in the amacrine sublayer. Although the cell bodies of both populations are distributed rather evenly, the mosaic of the inner nuclear layer cells is more regular than that of the ganglion layer cells. We propose that the two populations of amacrines stained by neurofibrillar methods correspond to the acetylcholine synthesizing cells labelled by Masland and Mills (1979).