bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies of retinal representations within the cat's optic tract
Authors: Torrealba F. , Guillery R. W. , Eysel U. , Polley E. H. , Mason C. A. 
Published: December 2004

AbstractThe manner in which each retina can be mapped onto a single cross section of the optic tract of the cat has been defined by neuroanatomical methods. It has been found that the contralateral nasal hemi‐retina and both temporal hemi‐retinae are represented in each tract by multiple, rough maps which partially overlap one another. All maps show the same general orientation, with area centralis represented dorsomedially, lower retina represented dorsolaterally, and upper retina represented ventromedially. The peripheral part of the horizontal meridian is represented ventrolaterally.Labeling all of the fibers from one eye by axonal degeneration or autoradiographic methods shows that the crossed map is displaced dorsally and medially relative to the uncrossed map, leaving a dorsomedial crescent of pure crossed fibers. Localized retinal lesions or injections of 3H‐amino acid show the general orientation of the maps. Lesions within the dorsomedial pure crossed crescent show that fibers in this crescent arise from retinal areas close to the optic disc, near the site of the early fetal fissure. Localized injections of horseradish peroxidase into the optic tract show the relationships of the several maps in terms of the retinal distribution of retrogradely labeled retinal ganglion cells. They show that axons of large and small cells map ventrolaterally in the tract while intermediate sizes map dorsomedially. They confirm that the crossed map is displaced relative to the uncrossed map.It is suggested that the optic tract develops by fibers taking a position in the tract in accordance with their time of arrival at the chiasm. The several maps are displaced because they develop sequentially and the optic tract can be read as a developmental record, the most dorsomedial axons being the oldest.
The origin of lipid phagocytes in the central nervous system: II. The adventitia of blood vessels
Authors: Brierley J. B. , Brown A. W. 
Published: December 2004

AbstractThe source of the lipid phagocytes that occupy a cerebral infarct has been determined by light and electron microscopy in the brains of rodents and by light microscopy only in the brains of primates. The infarcts (in neocortex, hippocampus, and thalamus) were the consequence of hypoxiaischemia of various types. Hemorrhagic infarcts were excluded. After in vivo perfusion‐fixation, paraffin‐ and celloidin‐embedded material was used for light microscopy. Semithin plastic sections from the neocortex and thalamus were studied with the light microscope and ultrastructural studies were confined to the same regions.In all animals after about 2 days there was evidence of phagocytic activity in the fibroblasts in the adventitia of the remaining large vessels and also proliferation by mitotic division. At 5‐7 days fibroblasts appeared to migrate from the vessels in a semifluid or fluid milieu and to give rise to typical phagocytes. These increased in size and number but signs of degeneration became apparent after 10 days and they had largely disappeared by 32 days. Smooth muscle cells and pericytes showed evidence of degeneration and phagocytic activity was never seen in the latter.
Quantitation of propriospinal fibers in the tract of lissauer of the rat
Authors: Chung Kyungsoon , Coggeshall Richard E. 
Published: December 2004

AbstractThe present study uses a spinal cord isolation procedure to remove extrinsic axons but leave intrinsic axons intact. The isolation is done by sectioning the spinal cord in two places and then cutting all dorsal roots between the two sections. The axons that survive the isolation procedure are thought to be propriospinal axons. Following isolation, approximately one‐third of the axons in sacral tracts of Lissauer in the rat survive. Thus approximately one‐third of the axons in sacral tracts of Lissauer in the rat are propriospinal. Proportionately more myelinated than unmyelinated axons are lost. There are approximately equal numbers of surviving axons in the medial as opposed to the lateral part of the tract. This implies that there is, as yet, no morphological basis for dividing the tract into medial and lateral halves. The fact that the number of propriospinal axons in the tract of Lissauer has been quantitated offers more precision in our thinking about the organization of the dorsal horn.
Insula of the old world monkey. III: Efferent cortical output and comments on function
Authors: Mesulam M.‐Marsel , Mufson Elliott J. 
Published: December 2004

AbstractThe insula sends neural efferents to cortical areas from which it receives reciprocal afferent projections. A collective consideration of afferents and efferents indicates that the insula has connections with principal sensory areas in the olfactory, gustatory, somesthetic (SI and SII), and auditory AI and AII) modalities. There are additional connections with association areas for the visual (TEm), auditory (supratemporal plane), and somesthetic (posterior parietal cortex) modalities; with parameter cortex (area 6 and perhaps MII); with polymodal association cortex; and with a wide range of paralimbic areas in the orbital, temporopolar, and cingulate areas.The topographic distribution of these connections suggests that the posterodorsal insula is specialized for auditory‐somesthetic‐skeletomotor function whereas the anteroventral insula is related to olfactory‐gustatory‐autonomic function. Most of the insula, especially its anteroventral portions, have extensive interconnections with limbic structures. Through its connections with the amygdala, the insula provides a pathway for somatosen‐sory, auditory, gustatory, olfactory, and visceral sensations to reach the limbic system.The cortical areas connected with the granular sector of the insula are also granular in architecture whereas virtually all the connections of the agranular insula arise from allocortical, agranular, or dysgranular areas. Thus, there is a correspondence between the architecture of insular sectors and the areas with which they have connections. The insula is heavily interconnected with temporopolar and lateral orbital areas. Furthermore, many cortical connections of the lateral orbital cortex are quite similar to those of the insula. These common connectivity patterns support the conclusion, based on architectonic observations, that the insulo‐orbito‐tempo‐ropolar component of the paralimbic brain should be considered as an integrated unit of cerebral organization.
Origins of substance P‐containing fibers in the lateral septal area of young rats: Immunohistochemical analysis of experimental manipulations
Authors: Sakanaka Masahiro , Shiosaka Sadao , Takatsuki Kenichi , Inagaki Shinobu , Hara Yoshinobu , Kawai Yuriko , Senba Emiko , Tohyama Masaya 
Published: December 2004

AbstractThe majority of substance P‐like immunoreactive (SPLI) fibers in the lateral septal area (LS) are supplied by SPLI cells in the area (BAL between the anterior hypothalamic nucleus and the lateral hypothalamus, and by those in the nucleus latero‐dorsalis tegmenti (TLD)). These conclusions are based on following: (1) Unilateral destruction of the BAL resulted in an ipsilateral decrease in the septal SPLI fibers similar to that seen after the destruction of the TLD, and (2) simultaneous destruction of the BAL and TLD caused a marked reduction of SPLI fibers in the LS on the operated side. The possibility that the destruction of the BAL affected the ascending SPLI system from the TLD seems to be excluded, because (1) the destruction of the TLD resulted in a decrease in SPLI fibers in the ipsilateral medial forebrain bundle (MFB), but failed to reduce the number of SPLI fibers in the BAL, and (2) the destruction of the BAL caused a decrease in SPLI fibers in the perifornical area rostral to the lesion, but failed to reduce the number of SPLI fibers in the MFB. These facts further suggest that ascending SPLI fibers from the BAL travel in the perifornical area and those from the TLD pass through the MFB. It should be noted that a few SPLI fibers remained intact following the simultaneous destruction of the BAL and TLD. The present study suggests that these remaining SPLI fibers might be innervated by intrinsic SPLI cells. In support of this, several SPLI cells were detected in the septal area after colchicine pretreatment.
Pathways connecting the right and left cochlear nuclei
Authors: Cant Nell B. , Gaston Karen C. 
Published: December 2004

AbstractConnections between the right and left cochlear nuclei were studied with retrograde and anterograde axonal transport techniques. Large, multipolar neurons in the anterior and posterior divisions of the anteroventral cochlear nucleus and in the posteroventral cochlear nucleus project to the ventral and dorsal cochlear nuclei on the opposite side. In addition, giant cells in the deep layers of the dorsal cochlear nucleus project to the contra‐lateral posteroventral cochlear nucleus and possibly also to the contralateral dorsal cochlear nucleus. The pattern of terminal distribution of the crossed connections was determined by using the anterograde axonal transport of horseradish peroxidase‐labelled wheat germ lectin. Although no part of the cochlear nuclear complex is completely free of anterograde label, the densest labelling is found in the anterior division of the anteroventral cochlear nucleus, throughout the posteroventral cochlear nucleus (where it is closely associated with cell bodies), and in the fusiform and superficial layers of the dorsal cochlear nucleus.These direct synaptic connections from one cochlear nucleus to the other could play a significant role in processes that depend on binaural interactions within the central nervous system.
Bilateral interactions within the vocal control pathway of Birds: Two evolutionary alternatives
Authors: Paton J. A. , Manogue K. R. 
Published: December 2004

AbstractBilateral interactions between the right and left sides of the vocal control pathway of three avian species, the budgerigar (Melopsittacus undulatus), the zebra finch (Poephila guttata), and the canary (Serinus can‐arius), were compared by using microstimulation. Stimulation of the neo‐striatal nucleus, hyperstriatum ventrale pars caudale (HVc), caused a constant‐latency increase in neural activity of the tracheosyringeal (ts) nerve. This nerve supplies the avian vocal organ, the syrinx.Unilateral stimulation of HVc in budgerigars caused equal responses in both right and left ts nerves, whereas in canaries and zebra finches, much larger responses with lower thresholds and shorter latencies were evoked in the ipsilateral ts nerve than in the contralateral ts nerve. Furthermore, contralateral responses in the oscines were seen only at high rates of stimulation, whereas ipsilateral responses could be evoked by a single stimulus pulse.Simultaneous bilateral stimulation of HVc in budgerigars evoked a greater than linear summation of responses on each ts nerve, evidence for convergence of ipsi‐ and contralateral inputs onto the same set of motor neurons. No such summation was detected in zebra finches or canaries.The bilateral distribution of excitation within the song control pathway of budgerigars should lead to coactivation of bilaterally paired muscles on each side of the syrinx. This type of interaction should ensure that the two sides of the parrot syrinx operate as parts of a unitary, or single‐voiced, syrinx. In contrast, the two sides of the song control pathway in canaries and zebra finches are almost completely isolated from each other, and are thus free to act independently. This type of organization lends itself to the separate control of simultaneously produced, harmonically unrelated sound elements by the two independent sound sources present in the songbird's two‐voiced syrinx.
Structure of the mitral cell in the olfactory bulb of the goldfish (Carassius auratus)
Authors: Kosaka Toshio , Hama Kiyoshi 
Published: December 2004

AbstractThe mitral cell in the olfactory bulb of the goldfish was examined by means of light microscopy, high‐voltage electron microscopy, and conventional electron microscopy.Mitral cells are located rather diffusely throughout the glomerular and plexiform layers. They do not make their own discrete layer. The cell bodies are rounded or triangular, and are about 10–25 μm in diameter. In Golgi‐impregnated material, thick cylindrical dendrites can be seen arising from the cell bodies and branching in the glomerular layer. Dendritic branches of some cells make two or more rather compact tufts, while the dendrites of other cells intermingle loosely with one another.In semithin and thin sections, darkly stained nodules appear to be scattered diffusely in the glomerular layer without clustering into discrete spheres, which are characteristic of the mammalian glomerulus. Hence, instead of the glomerulus, the “glomerular area” is defined as an area consisting of darkly stained nodules with rather pale granular regions surrounding them. Branches of mitral cell dendrites in the glomerular area consist of cylindrical shafts and irregular appendages arising from them. The shafts appear in the pale granular region and the appendages are found in the darkly stained nodules.Synapses can be found on all parts of the mitral cell: the soma, axon hillock, axon initial segment, thick dendritic stems, and dendritic branches. The abundance of synapses seems to vary considerably from part to part, and is highest on the dendritic branches in the glomerular area. The mitral cell is postsynaptic to olfactory nerve terminals and granule cell dendrites, and presynaptic to granule cell dendrites and some processes of unknown origin. Olfactory nerve terminals make asymmetrical synapses specifically on the appendages of the dendritic branches. Of the synapses on the shafts of the mitral cell dendritic branches in the glomerular area, 90% are with granule cell dendrites. Of the synapses between two different kinds of processes 30% are mitral‐to‐granule asymmetrical synapses, 20% are granule‐to‐mitral symmetrical synapses, and 50% are reciprocal pairs. Gap junctions and mixed synapses are also seen on branches of mitral cell dendrites.Features of the goldfish mitral cell are compared with those of the mammal. The differences in neuronal organization between the olfactory bulbs of teleosts and mammals are discussed.
The structural correlate of saltatory conduction along the mauthner axon in the tench (Tinea tinea L.): Identification of nodal equivalents at the axon collaterals
Authors: Yasargil Guenay M. , Greeff Nikolaus G. , Luescher Hans R. , Akert Konrad , Sandri Clara 
Published: December 2004

AbstractThe spiny collaterals of the Mauthner axon were reinvestigated in the tench (Tinea tinea L.) with the electron microscope and special staining procedures. These collaterals, as demonstrated by intraaxonal labelling with lucifer yellow, are more or less regularly spaced (100–300 μm) and make synaptic contacts with processes of spinal motoneurons and interneurons. The unrnyelinated tips of the collaterals are further characterized by the following structural features: (1) an electron‐dense undercoating of the axolemma, (2) a positive Prussian blue reaction of the inner surface of the axolemma following ferric ion‐ferrocyanide staining (Waxman and Quick, '78a), (3) expanded extracellular spaces which react specifically to inorganic phosphate, metallic ions, and diaminobenzidine. All these properties are known to be shared by the axolemma of central and peripheral nodes of Ranvier. Previous studies from this laboratory have shown that the nerve impulse is propagated along the Mauthner axon in a saltatory mode. Since classical nodal gaps could not be identified within the myelin sheath of this giant fiber, it is concluded on the basis of the present findings that the unrnyelinated tips of the spiny collaterals represent nodal equivalents, and thus provide the morphological substrate for the saltatory propagation of the nerve impulse along the Mauthner axon. The typical latency steps, as demonstrated in the latency plot of the longitudinal current signals (Greeff and Yasargil, '80), and the distances between the identified membrane specializations at the axon collaterals are consistent with this conclusion.
The distribution of dorsal root axons to laminae IV, V, and VI of the macaque spinal cord: A quantitative electron microscopic study
Authors: Ralston Henry J. , Ralston Diane Daly 
Published: December 2004

AbstractThe projections of dorsal root axons to the deeper laminae (IV, V, and VI) of the Macaque spinal cord were examined by the use of experimentally induced degeneration following dorsal rhizotomy or by injection of dorsal root ganglia with tritiated amino acids followed by light and electron mi‐croscopic autoradiography.Following dorsal rhizotomy, neurofilamentous degeneration of synaptic profiles occurs in each of the three deep laminae, more commonly in laminae IV and V than in lamina VI. The neurofilamentous degeneration is seen both in central glomerular (C) profiles and in many of the round vesicle (R) profiles. Neurofilamentous degeneration occurs as early as 18 hours following rhizotomy and the degenerating terminals are most numerous at 3–4 days postrhizotomy. None are seen after 7 days survival. The neurofilamentous profiles form axodendritic and, occasionally, axosomatic synapses with neurons of the dorsal horn. They are also seen to be postsynaptic to flat vesicle (F) profiles in axoaxonal synapses.A second type of degeneration, electron‐lucent degeneration, is seen in laminae V and VI, and only occasionally in lamina IV. The lucent degeneration occurs somewhat later after rhizotomy than does the neurofilamentous degeneration and reaches its peak at 5 days postrhizotomy. No lucent terminals are seen after 7 days survival. Electron‐dense degeneration, so common in lamina II, is not seen in the deeper dorsal horn.Autoradiographic techniques show that both C and R terminals are labelled in the deeper dorsal horn. Both of these terminals form axodendritic synapses and a significant number are found to be postsynaptic in axoaxonal synapses.Most of the C terminals degenerate following rhizotomy or are labelled following injection of the parent dorsal root ganglia with tritiated amino acids. Approximately one‐fifth of the R profiles are derived from dorsal roots. F profiles do not appear to be of dorsal root origin in any case.It is concluded that neurofilamentous alterations represent the degeneration of larger‐diameter (Aβ) axons which distribute to the deeper dorsal horn and that electron‐lucent degeneration represents the termination of Aδ fibers. Electron‐dense degeneration thought to represent the termination of nonmyelinated axons (C fibers) in the superficial dorsal horn is not seen in the deeper dorsal horn and it is concluded that C fibers do not project to the deeper laminae.
Subcortical projections to lateral geniculate and thalamic reticular nuclei in the hooded rat
Authors: Mackay‐Sim Alan , Sefton Ann Jervie , Martin Paul R. 
Published: December 2004

AbstractRestricted injections either of horseradish peroxidase conjugated with wheat germ agglutinin, or of unconjugated horseradish peroxidase were made into hooded rats in order to distinguish subcortical sources of afferents to dorsal lateral geniculate nucleus from those to the adjacent visually responsive thalamic reticular nucleus, which modulates geniculate activity. Five “nonvisual” brainstem regions project to the dorsal lateral geniculate nucleus: mesencephalic reticular formation, dorsal raphe nucleus, periaqueductal gray matter, dorsal tegmental nucleus, and locus coeruleus. Projections are generally bilateral, but ipsilateral projections dominate. Of these regions, three also project ipsilaterally to the thalamic reticular nucleus: mesencephalic reticular formation, periaqueductal gray matter, and dorsal tegmental nucleus.Similar discrete injections of horseradish peroxidase into ventral lateral geniculate nucleus allowed a comparison of afferents to dorsal and ventral lateral geniculate nuclei. In addition to the five nonvisual brainstem regions which project to the dorsal division, the ventral lateral geniculate nucleus receives afferents from the perirubral reticular formation and the central gray matter at the thalamic level. The dorsal and ventral lateral geniculate nuclei receive substantially different afferents from subcortical visual centres. The dorsal division receives projections from superior colliculus, pretectum, and parabigeminal nucleus whereas the ventral division receives afferents from superior colliculus, additional pretectal nuclei, lateral terminal nucleus of the accessory optic system, and the contralateral ventral lateral geniculate nucleus.
Local cerebral glucose consumption in the rat. I. Effects of halothane anesthesia
Authors: Savaki Helen. E. , Desban Marcel , Glowinski Jacques , Besson Marie‐Jo 
Published: December 2004

AbstractRates of cerebral glucose utilization were measured by means of the autoradiographic 2‐deoxy‐D‐(l‐14C)glucose technique in normal rats under light halothane‐anesthesia. Three types of region‐specific metabolic alterations were elicited by inhalation of 0.5% halothane. The most striking effect observed was a significant increase of glucose consumption within the locus coeruleus, substantia nigra compacta and reticulata, interpeduncular nucleus, hippocampus, and fornix of the anesthetized animals in comparison to the corresponding brain areas of the conscious control rats. Halothane‐anesthesia was also associated with significant metabolic depression in 21 (out of the 74 examined) discrete regions of the rat brain, distributed within the pons, cerebellum, diencephalon, and cortex, and was more prevalent in thalamus and neocortex. However, halothane failed to alter consistently the rates of glucose utilization in the rest of the rat brain areas investigated. The present findings suggest that halothane specifically alters the regional cerebral glucose utilization, with some limbic system components and the basal ganglia displaying increased metabolism, in contrast to the sensori‐motor system which demonstrates significantly decreased metabolic activity.
Local cerebral glucose consumption in the rat. II. Effects of unilateral substantia nigra stimulation in conscious and in halothane‐anesthetized animals
Authors: Savaki Helen E. , Desban Marcel , Glowinski Jacques , Besson Marie‐Jo 
Published: December 2004

AbstractThe energy metabolism of 74 anatomically discrete central nervous structures was investigated by means of the autoradiographic 2‐deoxy‐D‐(1‐14C) glucose method (14C‐DG) in conscious awake, as well as in halothane anesthetized rats, following unilateral substantia nigra (SN) electrical stimulation.All the basal ganglia structures displayed bilateral metabolic activation in conscious animals, with only the contralateral subthalamic nucleus being unaffected. In anesthetized rats only the SN reticulata, globus pallidus, and subthalamic nucleus were affected ipsilaterally whereas anesthesia masked the effects of SN stimulation in SN compacta and striatum ipsilaterally, as well as within‐all the above structures contralaterally. The entopeduncular nucleus was bilaterally activated no matter the state of consciousness. Unilateral SN stimulation also increased glucose utilization within several thalamic regions (ventromedial, ventrolateral, ventroanterior, intralaminar, ventrobasal, and mediodorsal nuclei), the habenular complex, a few mesencephalic, brainstem (locus coeruleus and dorsal raphe) and cerebellar structures, mostly bilaterally and independently of the state of consciousness.Some of the factors suggested to be responsible for the masking effects of halothane‐anesthesia on the metabolic activations elicited by unilateral SN stimulations are the following: (1) absence of movements in anesthetized rats, (2) halothane‐induced depression of polysynaptic pathways mostly mediated through the thalamus, and (3) the stimulatory effect of halothane‐anesthesia itself on metabolic activity in both parts of the SN.