bluuebunny/crossref_metadata_2025_split huggingface dataset:
Uniformity of monkey striate cortex: A parallel relationship between field size, scatter, and magnification factor
Authors: Hubel David H. , Wiesel Torsten N. 
Published: May 2005

AbstractThis paper is concerned with the relationship between orientation columns, ocular‐dominance columns, the topographic mapping of visual fields onto cortex, and receptive‐field size and scatter. Although the orientation columns are an order of magnitude smaller than the ocular‐dominance columns, the horizontal distance corresponding to a complete cycle of orientation columns, representing a rotation through 180°, seems to be roughly the same size as a left‐plus‐right ocular dominance set, with a thickness of about 0.5–1 mm, independent of eccentricity at least out to 15°. We use the term hypercolumn to refer to a complete set of either type (180°, or left‐plus‐right eyes).In the macaque monkey several penetrations were made at various eccentricities in various parts of the striate cortex subserving the fovea, parafovea and midperiphery. As observed many times previously, in any vertical penetration there was an apparently random scatter in receptive‐field positions, which was of the same order of magnitude as the individual receptive fields in that part of the cortex; the field size and the scatter increased in parallel fashion with eccentricity. The movement through the visual field corresponding to a 1 mm horizontal movement along the cortex (the reciprocal of the magnification factor) also increased with eccentricity, in a manner that was strikingly parallel with the increase in receptive field size and scatter. In parts of the cortex representing retina, at least out to about 22° from the fovea, a movement along the cortical surface of about 1 mm was enough to displace the fields so that the new position they collectively occupied half overlapped the old. Such an overlap was thus produced by moving along the cortex a distance about equal to the thickness of a left‐plus‐right set of ocular‐dominance columns, or a complete 180° array of orientation columns. It therefore seems that, independent of eccentricity, a 2 mm × 2 mm block of cortex contains by a comfortable margin the machinery needed to analyze a region of visual field roughly equal to the local field size plus scatter. A movement of 2–3 mm corresponds to a new visual field region and to several new sets of hypercolumns. The cortex thus seems remarkably uniform physiologically, just as it is anatomically.
Ordered arrangement of orientation columns in monkeys lacking visual experience
Authors: Wiesel Torsten N. , Hubel David H. 
Published: May 2005

AbstractThe main object of this study was to see whether ordered sequences of orientation columns are present in very young visually naive monkeys. Recordings were made from area 17 in two macaque monkeys three and four weeks of age, whose eyes had been closed near the time of birth. The first monkey was born normally, but one day elapsed before eye closure could be done. The second was delivered by Cesarean section and the lids sutured shut immediately. The results in these two animals were very similar; in both, highly ordered sequences of orientation shifts were present, and were in no obvious way different from those seen in the adult. For example, average values for the size of orientation shifts, for the horizontal component of the distance between shifts, and for the slopes of orientation vs. track distance curves, were all similar to adult values. This indicates that the ordered column system is innately determined and not the result of early visual experience. In these two monkeys and a third one, sutured at two days and examined at 38 days, most of the cells seemed normal by adult standards, with simple, complex or hypercomplex receptive fields, showing about the same range in orientation specificity as is found in adults. About 10–15% of cells showed abnormalities similar to those seen in monkeys binocularly deprived of vision for longer periods. Furthermore, all three deprived monkeys showed a decided lack of cells that could be influenced from both eyes, whereas a normal three‐week‐old control animal seemed similar to the adult, with binocular cells comprising over half of the total population. A monkey deprived by binocular closure from the third to the seventh week also showed a diminution in number of binocularly influenced cells, suggesting that the deprivation from birth resulted in a deterioration of innate connections subserving binocular convergence. To be sure that the abnormalities in the deprived animals represented a deterioration of connections, we recorded from 23 cells in a normal two‐day‐old monkey: here the ocular dominance distribution of cells was about the same as in the adult, and the response characteristics of the cells were normal by adult standards.
A retinotopic analysis of the central connections of the optic nerve in the frog
Authors: Scalia Frank , Fite Katherine 
Published: May 2005

AbstractThe possibility of retinotopic organization in the optic nerve projections to the contralateral and ipsilateral diencephalon was studied by means of partial retinal lesions and staining for terminal degeneration by the Fink‐Heimer technique. A retinotopic pattern of projection was observed in the nucleus of Bellonci, the corpus geniculatum thalamicum and the posterior thalamic nucleus. The temporal quadrant of the retina, and, to a lesser extent, the ventral quadrant projected to the ipsilateral side as well as to the contralateral side. In each diencephalic region noted above, the temporal and dorsal quadrants of the retina were represented more posteriorly (posteroventrally), and ventral and nasal quadrants projected more anteriorly (anterodorsally). The areas of representation for the temporal and ventral quadrants were located superior (superoposterior) to those for the dorsal and nasal quadrants. In their overall configuration and orientation, the retino‐diencephalic maps show mirror‐image reversal with respect to the retino‐tectal projection. Since, in their areal extent, both the retino‐diencephalic maps and the retino‐tectal map are approximately parallel to the ventricular surface, their mirror‐image reversal appears to indicate a reversal in the polarity of developmental processes across the di‐mesencephalic junction.The retinotopic organization within the optic tract in the diencephalon and tectum was also analyzed. In the optic tract, the quadrants of the retina are reassembled such that the dorsal and nasal quadrants are widely separated in, respectively, the ventral and dorsal edges of the tract; the temporal and ventral quadrants are systematically represented in intermediate levels in the tract, the temporal quadrant above the dorsal, and the ventral quadrant below the nasal. When the optic tract bifurcates to encircle the tectum, the fibers from the ventral and nasal quadrants enter the dorsomedial arm and the fibers from the temporal and dorsal quadrants enter the ventrolateral arm of the optic tract. The paths taken by optic fibers in traversing the tectum to reach their areas of termination were reconstructed. Many optic fibers show an alignment parallel to an anteroventral posterodorsal axis as they cross the surface of the tectum, but the OS vs IS characterization of the fibroarchitecture of the tectum appears to be an oversimplification.
The structure of the inferior lobe of the teleost hypothalamus
Authors: Demski L. S. , Evan A. P. , Saland L. C. 
Published: May 2005

AbstractElectron microscopic and Golgi studies on the inferior lobes of sunfish and goldfish are described. The inferior lobe consists primarily of a nucleus ventricularis of densely packed cells surrounding the lateral recess of the third ventricle, and a peripherally situated nucleus diffusus consisting mostly of scattered neurons. A cell‐sparse zone of dense neuropil is located between the two cellular areas. Neurons of both nuclei have spiny dendrites and axons which originate from basal dendrites. In some cases axons are found to send a collateral into the cell‐sparse zone. Neurons of the nucleus diffusus possess collaterals that extend a considerable distance within the nucleus itself. The ultrastructure of cells of both nuclei reveals cytoplasmic organelles typical of most neurons. Synapses containing dense‐cored and clear vesicles are present on the spines and shafts of the dendrites of both neuronal types. In only rare cases synapses were observed on the soma of neurons of the nucleus ventricularis. Possible anatomical substrates involved in the control of feeding and aggression in teleosts are considered in light of the present findings. Morphological similarities of the inferior lobes and related areas in various fishes and amphibians are discussed and their possible significance for the understanding of the evolution of hypothalamic mechanisms is considered.
Distribution of ultrastructural tracers in crustacean axons
Authors: Nordlander Ruth H. , Masnyi Jerry A. , Singer Marcus 
Published: May 2005

AbstractRuthenium red and horseradish peroxidase were used to compare the uptake of exogenous molecules into crayfish motor axons and their sheaths in severed and intact peripheral nerves. Both tracers penetrated the axonal sheath and were subsequently seen lining small vesicles and tubules in the axoplasm. Tracer appeared to enter the axon via pinocytotic vesicles. There were no perceptible quantitative or qualitative differences in ruthenium red uptake between intact and severed axons. However, counts of tracer‐filled vesicles in axons exposed to peroxidase showed that at least three times as much tracer penetrated the severed as opposed to the intact axons.
Scanning electron microscopy of the subarachnoid space in the dog. III. Cranial levels
Authors: Allen Delmas J. , Low Frank N. 
Published: May 2005

AbstractYoung dogs were anesthetized by intrathoracic injection of sodium pentobarbital and perfused with buffered aldehydes. Lining tissue samples from the cranial subarachnoid space were prepared for scanning electron microscopy (SEM) by postfixing in buffered OsO4. Samples were then dehydrated, dried in a Critical Point Drying System, and coated with carbon and palladiumgold. Specimens were viewed in a Cambridge S4 scanning electron microscope. After thorough scanning, selected samples were routinely prepared for transmission electron microscopy (TEM) and viewed in a Philips EM‐200 transmission electron microscope.This study depicts the surface morphology of the meningeal linings of the cranial subarachnoid space. The cranial pia mater possesses natural gaps or fenestrations between cells. SEM reveals a more complex morphology of arachnoid trabeculae than previously interpreted from light and transmission electron microscopy. Many free cells are observed on the meningeal linings of the subarachnoid space. The present study establishes that these free cells are macrophages by means of definitive TEM correlates. Microvillous‐like processes extending between macrophages and the pial surface are present. The frequency and the nature of these thin processes suggest the possibility of a plasmalemmamediated system of communication.
Surface fine structure of supraependymal elements and ependyma of hypothalamic third ventricle of mouse
Authors: Bleier Ruth 
Published: May 2005

AbstractThe ependymal surface of the hypothalamic third ventricle of the adult female and male mouse was examined with the scanning electron microscope. The material was dried with the critical point method. Supraependymal cells, exhibiting a variety of forms, lie among the cilia of the rostrodorsal two‐thirds of the ventricle. The cell bodies are usually between 8 and 10 μ in diameter and have dividing pseudopodial processes which may be broad or narrow, flat or stout, smooth or varicosed. The textured surfaces of the cells seen in this material appear to have no cilia, microvilli or membraneous folds though they may have small bleb‐like protrusions. Some cells and adjacent cilia bear clusters of friable‐looking material that may be secretory.In several female mice, mounds of debris, that could be degenerating cells or secretory material, were seen in intimate association with clusters of cells. The cells' processes extend over and through the surface of the mound.While some supraependymal cells may be neurons or glia, it is suggested that many of the cells seen may be morphological variants of one cell line, mononuclear phagocytes.Sausage‐shaped structures at the end of long cilia‐like stalks are described and their possible identity discussed.
The connections and laminar organization of the optic tectum in a reptile (Iguana iguana)
Authors: Foster Robert E. , Hall William C. 
Published: May 2005

AbstractThe goals of this study were: (1) to describe the total pattern of projections from the optic tectum of Iguana iguana and Pseudemys scripta; and (2) to describe the contributions of particular lamina of the Iguana's optic tectum to this total pattern. Lesions were made in the optic tectum of the Iguana which damaged either all or only certain tectal laminae and, for comparison with the Iguana, lesions in the turtle's optic tectum were made which involved all laminae. The anterograde degeneration resulting from these lesions was stained with the Fink‐Heimer ('67) method. The total pattern of projections from the optic tectum in the Iguana and the turtle is similar to that reported for representatives of other vertebrate classes. That is, the optic tectum gives rise to ipsilateral ascending projections to pretectal nuclei, to nucleus rotundus and to nucleus geniculatus lateralis pars ventralis of the diencephalon and, in addition, to a contralateral ascending pathway which courses via the supraoptic decussation to the contralateral diencephalon. Tectotectal connections and several descending pathways were also recognized in each species. The descending pathways include ipsilateral tectobulbar and tecto‐isthmi pathways and a contralateral predorsal bundle.Lesions which damaged only certain tectal laminae in the Iguana revealed a laminar organization of the efferent projections. A lesions restricted to the superficial retinal‐recipient layers, stratum griscum et album superficiale, resulted in degeneration in only nucleus isthmi pars magnocellularis and nucleus geniculatus lateralis pars ventralis. A lesion which involved both the retinal‐recipient layers and stratum griseum centrale resulted in degeneration in only one additional structure, nucleus rotundus. A small lesion involving the deep periventricular layer as well as the superficial layers produced degeneration in the predorsal bundle and the ipsilateral tectobulbar tract as well as in the structures receiving input from the more superficial layers. These results are compared to the results of similar analyses of the superior colliculus in mammals.
Unmyelinated preganglionic fibers in frog ventral roots
Authors: Vance W. Hugh , Clifton Guy L. , Applebaum M. L. , Willis William D. , Coggeshall Richard E. 
Published: May 2005

AbstractIt has been suggested that the preganglionic visceral fibers in the frog are unmyelinated. To obtain further evidence for this suggestion: (1) the percentages of unmyelinated fibers and the myelinated fiber histograms were done for all frog ventral roots, (2) the number of unmyelinated fibers were counted on either side of a chronic section of the seventh ventral root and (3) compound action potentials were obtained for roots 7–10. The results are that slightly more than 80% of the unmyelinated fibers in the seventh ventral root arise in the spinal cord and are presumably unmyelinated preganglionic efferents. Furthermore, a C fiber volley could be followed from the seventh ventral root into caudal parts of the sympathetic chain. Thus this data provides confirmation for the idea that many frog preganglionic fibers are unmyelinated. This study also shows that 24% of the ventral root axons in the frog are unmyelinated and that, on the basis of percentages of unmyelinated fibers and myelinated fiber histograms, there are five categories of frog ventral roots.
Hippocampal innervation by serotonin neurons of the midbrain raphe in the rat
Authors: Moore Robert Y. , Halaris Angelos E. 
Published: May 2005

AbstractThe organization of the brainstem serotonin neuron projection to the hippocampal formation was analyzed in the rat. This projection arises in the raphe nuclei of the midbrain. Following destruction of the midbrain raphe nuclei, chiefly nucleus centralis superior, there is a 72% decrease in hippocampal serotonin content. Injection of tritiated amino acid into the midbrain raphe nuclei results in transport of tritiated protein to the hippocampal formation and this transport is blocked in animals pretreated by intraventricular administration of 5,6‐dihydroxytryptamine (5,6‐DHT). Autoradiographic analysis indicates that the transport reaches the hippocampal formation primarily via two major pathways, the cingulum and the fornix. Cingulum fibers terminate predominantly in the dorsal hippocampus whereas the fornix distributes throughout the entire hippocampal formation. Some fibers reach the ventral hippocampus from the entorhinal area. Within the hippocampus there is dense labeling in a restricted lamina of the CA1 stratum lacunosum‐moleculare with moderate labeling in stratum radiatum. Stratum oriens is sparsely labeled in CA1 and moderately so in CA2 and CA3. Stratum radiatum and stratum lacunosum‐moleculare are moderately densely labeled in CA2 and CA3. The area dentata is sparsely to moderately labeled in the molecular layer and heavily labeled in a thin lamina of the hilar zone immediately beneath the granule cell layer. The remaining hilar zone is moderately labeled. All of the discrete labeling of the hippocampus and area dentata described above is absent in animals pretreated with 5,6‐DHT. These observations indicate that serotonin neurons of the midbrain raphe provide a highly organized innervation of the hippocampal formation in the rat.
Cellular architecture and topographic organization of the inferior colliculus of the squirrel monkey
Authors: FitzPatrick Kathleen A. 
Published: May 2005

AbstractThe inferior colliculus of the squirrel monkey is made up of a large central nucleus, bordered by the smaller external and pericentral nuclei. The majority of cells in the central nucleus exhibit a pronounced laminar arrangement due to the orientation of their dendrites. In medial sections of the nucleus these laminae lie in a dorsorostral to ventrocaudal direction. More laterally the layers assume a horizontal orientation and at the far lateral edge of the central nucleus come to lie in a ventrorostral to dorsocaudal orientation.A single tonotopic representation of audible frequencies is present in the central nucleus. A regular progression of best frequencies from low to high is encountered as a microelectrode advances from dorsocaudal to ventrorostral in the sagittal plane. Penetrations in more medial regions of the central nucleus encounter neurons whose best frequencies represent a higher range of frequencies than those in the lateral parts. The orientation of the isofrequency laminae determined physiologically appears congruent with the orientation of the dendritic laminae.The relative volume of the central nucleus devoted to each octave from 250 Hz to 32 kHz was determined. Frequencies up to eight kHz command successively larger amounts of collicular tissue. The octave band from 8 to 16 kHz is represented by the greatest amount of collicular tissue. Disproportionate representation of frequency may be the consequence of innervation density along the basilar membrane.
Architectonic map of neocortex of the normal mouse
Authors: Caviness Verne S. 
Published: May 2005

AbstractThe neocortex of the normal mouse has been subdivided into architectonic fields on the basis of its cellular and fiber patterns. The map of medial, retrohippocampal, frontal and insular regions is little different from that of Brodmann as modified in minor ways by Krieg. The map of parietal, occipital and temporal regions follows closely the major rearrangements introduced to Brodmann's map by Krieg. Krieg's map has been modified to give individual status to the barrel fields and to designate occipital fields around the full circumference of field 17, and temporal fields circumferentially around field 41.
Monkey retinal ganglion cells: Morphometric analysis and tracing of axonal projections, with a consideration of the peroxidase technique
Authors: Bunt Ann H. , Hendrickson Anita E. , Lund Jennifer S. , Lund Raymond D. , Fuchs Albert F. 
Published: May 2005

AbstractThis paper presents evidence on the retinal distribution and certral projections of retinal ganglion cells of various cell body sizes in the adul macaque monkey. The ganglion cell sizes have been determined by computer assisted measurement of camera lucida drawings at various eccentricities of both flat mounted and sectioned retinae. The pattern of projections of individual ganglion cells to the dorsal lateral geniculate nucleus and superior colliculus has been studied using retrograde axonal transport of horseradish peroxidase. Following peroxidase injections into the parvocellular laminae of the geniculate, virtually every ganglion cell was labeled within a circumscribed zone of the retina known to project to the region of the geniculate immediately surrounding the injection needle tip. After magnocellular injections, only the largest cells of the peripheral retina and approximately 26% of the ganglion cells of the parafovea were labeled. Peroxidase injections into the superior colliculus produced labeling of scattered ganglion cells of all sizes in the retina, although no labeled cells were found within the centralmost 10° eccentricity. From these observations it is concluded that all ganglion cells of the macaque retina project to the parvocellular layers of the dorsal lateral geniculate, but that only the largest ganglion cells of the more peripheral retina and not all cells of the parafovea project to the magnocellular laminae. In contrast, only scattered ganglion cells, although these are of all sizes, appear to project to the superior colliculus.Two major problems with the peroxidase tracing technique are described:
The extent of stainable peroxidase activity around the injection site appears to be larger than the area of injected tracer actually available for uptake by axons to produce labeled cells.
Cut or damaged axons appear to incorporate peroxidase sufficiently to produce labeling of the cell body.