bluuebunny/crossref_metadata_2025_split huggingface dataset:
Histochemical evidence of altered development of cholinergic fibers in the rat dentate gyrus following lesions: I. Time course after complete unilateral entorhinal lesion at various ages
Authors: Nadler J. Victor , Cotman Carl W. , Lynch Gary S. 
Published: December 2004

AbstractThe entorhinal cortex of rats was removed at various times during development, and the reaction of the cholinergic septohippocampal input to the dentate gyrus was examined by use of acetylcholinesterase histochemistry. When the ipsilateral entorhinal cortex is completely removed, the outer 70‐75% of the molecular layer of the dentate gyrus is almost completely denervated. After such a lesion at 5 to 33 days of age, the acetylcholinesterase staining initially intensified throughout the denervated area, indicating that the septohippocampal fibers branched or elongated. This reaction could be detected within one day after a lesion at 11 days of age and within three or five days after lesions at earlier or later times. Whereas the initial response of the septohippocampal fibers was independent of the age at which the lesion was made, their final localization depended on the developmental state of the animal. After lesions at the age of 5 or 11 days, the reactive septohippocampal fibers became restrictd to the outer one‐sixth to one‐third of the molecular layer within two days after appearance of their initial reaction. A similar concentration of reactive fibers was demonstrable after lesions at 16, 18 or 21 days of age, but some reaction persisted in the middle third of the molecular layer. Finally, after lesions at 26 or 33 days of age the proliferating cholinergic fibers ultimately were uniformly distributed throughout the outer 60% of the molecular layer.These results suggest that septohippocampal fibers initially extend or sprout throughout the denervated area to replace the lost perforant path fibers. However, the reactive fiber population becomes restricted to the outer edge of the molecular layer if the entorhinal lesion is made before the period of cholinergic synaptogenesis and concentrates in this same zone if it is made while cholinergic synapses are forming. We suggest that either the proliferative reaction continues in the outer part of the molecular layer and subsides in other parts of the denervated area or septohippocampal fibers move outward through the molecular layer to assume a more superficial location.After entorhinal lesions at 16 days of age or later the pale‐staining zone (containing fibers that originate in hippocampus regio inferior) immediately deep to the denervated area widened. If the lesion was made earlier, this zone never developed at most septotemporal levels of the dentate gyrus. These results are probably related to the extension of regio inferior fibers into the denervated area.
Cat cones have rod input: A comparison of the response properties of cones and horizontal cell bodies in the retina of the cat
Authors: Nelson Ralph 
Published: December 2004

AbstractThe responses of horizontal cell bodies and cones in the retina of the cat have been studied by means of intracellular recording and Procion dye injection In an isolated, arterially perfused eyecup preparation. Comparison of the hyperpolarizing responses of these units to red and blue stimuli of different intensities indicated that all morphological varieties of horizontal cells and, additionally, cones themselves, had mixed rod and cone input. The rod input into horizontal cell bodies is thus explained on the basis of cone physiology. The half‐saturating intensity of 441 nm stimuli for the rod input into cones and horizontal cells was about 400 quanta/μm2/sec and about 160,000 quanta/μm2/sec for the cone input. Little of this difference can be related to the different quantum catching abilities of rods and cones. The spatial properties of horizontal cell bodies and cones have been characterized using stimuli consisting of long slits in conjunction with a continuous cable model. Space constants for horizontal cells ranged from 210 μm to 410pm, whereas those for cones ranged from 50μm, or possibly less, to 180 μm. It is argued that horizontal cell bodies of the cat retina form electrical networks, and that the sizes of the receptive fields generated in these networks may be limited by the diameters of the primary and secondary dendrites of horizontal cells. The rod and cone fields of horizontal cell bodies were found to be nearly coextensive in space, arguing against the notion that substantial rod input came from distant, rod‐dominated terminal arborizations.
The locust wing hinge stretch receptors. II. Variation, alternative pathways and “mistakes” in the central arborizations
Authors: Altman J. S. , Tyrer N. M. 
Published: December 2004

AbstractThe central arborizations of the stretch receptor (SR) neurones are very consistent from one individual to another. Superimposition of normalized neurones from eight individuals of Locusta show very little variation even in the detailed branching pattern. There is, however, a commonly found alternative course for the main medial branch in the metathoracic ganglion. Rare, radical departures from the normal branching pattern are termed “mistakes.” Only three have been found, all in the forewing SR projection, one with an extra branch and two with missing branches.Terminals of twigs in the alternative region of the medial branch occupy consistent positions in the neuropile, although these are reached by different routes. Mistakes have terminals in areas normally containing SR endings. Both these findings suggest that there may be labelled sites in the neuropile which the growing tips of the SR neurones seek out.
Specific neuroanatomical changes in chemosensory mutants of the nematode Caenorhabditis elegans
Authors: Lewis James A. , Hodgkin Jonathan A. 
Published: December 2004

AbstractEight of nineteen chemotactic mutants of the nematode Caenorhabditis elegans have morphological defects in the sensory endings of neurons at the tip of the head. The mutants were obtained as worms swimming away from attractant or found amongst male potency mutants or mutants exhibiting erratic behavior. The nineteen mutants fall into at least twelve complementation groups. Mutants E1034 and E1035, alleles of che‐1, show morphological alterations in the sensory endings of amphidial neurons and inner labial type 2 neurons, both prospective chemosensory neurons. Both mutants contain noncomplementing ts sterile mutations linked to the chemosensory mutation. E1066 shows abnormalities in all the sheath cells associated with the sensory neurons and in the bundling pattern of the amphidial neurons. El 126 is structurally abnormal only in the sensory endings of inner labial type 2 neurons, supporting a chemosensory role for these neurons. E1033 (cke‐2) and El 124 (cke‐3) cause defects in the ciliary structure of all but one type of ciliated sensory neuron in the head. E1062 is grossly defective in head structure and the structure of the male copulatory organ, suggesting these opposite ends of the nematode rich in sensory structures share gene functions in embryogenesis. Our study illustrates the possibilities for genetic dissection of the development of a small set of nerves in a simple organism.
Projections from the amygdaloid complex and adjacent olfactory structures to the entorhinal cortex and to the subiculum in the rat and cat
Authors: Krettek J. E. , Price J. L. 
Published: December 2004

AbstractAxonal projections are described from the lateral and hasolateral nuclei of the amygdaloid complex, and from the overlying periamygdaloid and pre‐piriform cortices and the endopiriform nucleus, to the lateral entorhinal area, the ventral part of the subiculum, and the parasubiculum in the cat and rat. All of these projections have well‐defined laminar patterns of termination, which are complementary to those of other projections to the same structure.Based on these results, and on cytoarchitectonic distinctions, the lateral entorhinal area has been divided into dorsal, ventral, and ventromedial subdivisions. The olfactory bulb and prepiriform cortex project to layers IA and IB, respectively, of all three subdivisions, but the lateral amygdaloid nucleus has a restricted projection to layer 111 of the ventral subdivision only. The periamygdaloid cortex projects to layer II of the ventromedial and adjoining parts of the ventral subdivisions.The ventral part of the subiculum receives fibers from the posterior division of the hasolateral nucleus, which terminate in the cellular layer and the deep half to one‐third of the plexiform layer. The periamygdaloid cortex and the endopiriform nucleus also project to the same part of the subiculum, but these fibers terminate in the outer part of the plexiform layer. None of these projections extend into the dorsal part of the subiculum.The posterior division of the basolateral nucleus also projects to the posterodorsal part of the parasubiculum (“parasubiculum a” of Blackstad, 1956). These fibers end in the deeper part of the plexiform layer and the superficial part of the cellular layer.
Afferent connections of the habenular nuclei in the rat. A horseradish peroxidase study, with a note on the fiber‐of‐passage problem
Authors: Herkenham Miles , Nauta Walle J. H. 
Published: December 2004

AbstractThe afferent connections of the habenular complex in the rat were examined by injecting horseradish peroxidase (HRP) into discrete portions of the habenular nuclei by microelectrophoresis.1. HRP deposits confined to the lateral half of the lateral habenular nucleus labeled a multitude of cells in the entopeduncular nucleus. Numerous labeled cells also appeared in such cases in the lateral hypothalamus, indicating that the lateral habenular nucleus is a major convergence point of projections from these otherwise.2. HRP injected into the medial part of the lateral habenular nucleus labeled cells in the same regions, but more in the diagonal band and fewer in the entopeduncular nucleus than were labeled by more lateral injections. The contrast suggests that the projections from the basal forebrain and entopeduncular nucleus to the lateral habenular nucleus are somewhat topographically organized.3. Injections of the medial habenular nucleus labeled an abundance of cells in the posterior parts of the supracommissural septum, but also a small number of cells in the diagonal band and mesencephalic raphe.4. HRP injected into the stria medullaris labeled cells in all of the afore‐mentioned areas and, in addition, cells in several olfactory structures, confirming that HRP may be taken up by fibers of passage and label their cells of origin, and suggesting that olfactory structures contribute fibers to the stria medullaris that do not terminate in the habenula.
Cerebellar histogenesis in the lurcher (Lc) mutant mouse
Authors: Swisher Dorothy A. , Wilson Doris B. 
Published: December 2004

AbstractThe postnatal development of the cerebellar cortex of normal and lurcher (Lc) mutant mice was studied by neurohistological and autoradiographic techniques at ages ranging from 2 days through 18 days after birth. Lurcher shows severe defects in the granule cells and Purkinje cells soon after birth.A decrease in the generative layers of the external granular layer is soon as early as two days in the lobulus simplex and by six days of age in the uvula. Granule cell death is common before and during granule cell migration, from 2 to 18 days of age. Loss of granule cells is reflected in reduced growth of the molecular and granular layers. Purkinje cell abnormalities appear at three to four days after birth in the form of crowding, failure of nuclear growth, and condensed or lessened cytoplasm. Purkinje cell death is apparent at four to six days of age depending on the region of the cerebellum.
Anatomy of the retina of the mink (Mustela vison)
Authors: Dubin Mark Wm. , Turner Linda 
Published: December 2004

AbstractThe retina of the normal pigmented mink has been studied by light and electron microscopy. This retina resembles the typical vertebrate retina in its pastterns of lamination and synaptic interconnectivity. Rod and cone outer segments and receptor spherule and pedicle endings are found. At least two different types of horizontal cell processes are seen with the electron microscope, suggestive of rabbit A and B types. Ribbon and conventional synapses are found in both plexiform layers; conventional synapes are also present in the inner nuclear layer. Quantitative studies of the inner plexiform layer revealed amacrine:bipolar synapse ratios (3.3:1) similar to those of the cat and monkey. Other quantitative parameters also resembled those previously reported for species with retinas that predominantly contain concentric‐type receptive fields.
The organization of the pulvinar in the grey squirrel (Sciurus carolinensis). I. Cytoarchitecture and connections
Authors: Robson J. A. , Hall W. C. 
Published: December 2004

AbstractThe posterior neocortex in the gray squirrel, Sciurus carolinensis, includes an extensive region which receives projections from the pulvinar. Previous studies have demonstrated that this cortical region can be subdivided on the basis of differences in cytoarchitecture and electrophysiologically defined representations of the visual field. The main purpose of the present paper was to determine whether these cortical subdivisions could be related to corresponding subdivisions in the pulvinar. The methods used to trace connections included anterograde degeneration, anterograde axonal transport of tritiated amino acids and the retrograde axonal transport of horseradish peroxidase. The results indicate that the pulvinar in this species contains at least three main subdivisions which can be distinguished by their cytoarchitecture and their patterns of connections. A caudal subdivision contains large, evenly‐spaced neurons and receives bilateral input from the superficial, retinal‐recipient layers of the superior colliculus. This caudal subdivision has reciprocal interconnections with a cytorchitectonically ditinct area in the temporal cortex. A rostro‐lateral subdivision contains smaller, more lightly stained neurons which tend to form cluster. This subdivision receives only ipsilateral tectal input and projects to occipital area 18. This subdivision does not receive input form areas 17, 18, and 19, or form the temporal cortex. Finally, a rostro‐medial subdivision is cytoarchitectonically similar to the rostro‐lateral subdivision but receives little, if any, input form the superior colliculus. This rostro‐medial area does, however, receive corticofugal projections form occipital areas 17, 18, and 19, and projects to area 19. These patterns of connections suggest that each of these subdivisions has close associations with the visual system. The question of whether similar subdivisions are present in the visual thalamus of other species is discussed.
Horizontal cells of the pigeon retina
Authors: Mariani Andrew P. , Leure‐DuPree Alphonse E. 
Published: December 2004

AbstractTwo types of horizontal cells are seen in Golgi‐impregnated retinas of the pigeon. Type I horizontal cells are compact, “brush‐shaped,” and have an axon ending as an irregular spinous arborization. The majority of the dendrites terminate in the distal part of the outer plexiform layer (OPL) as clusters which contact cones, but some terminate as single expansions in the proximal part of the OPL. The axon terminal spines are found only in the distal part of the OPL and contact both rods and cones. Pigeon Type I horizontal cells are Caja's “brush‐shaped” cells, and their axon terminals resemble Caja's “stellate” cells. Type II horizontal cells have irregular, wavy, multi‐branched dendrites, appear horizontally flattened, and lack axons. The dendrites terminate in the proximal part of the OPL as isolated spines and contact only cones. The Type II horizontal cells of the pigeon have not been previously described in the avian retina.
Cells of origin and terminal distribution of descending projections of the rat somatic sensory cortex
Authors: Wise S. P. , Jones E. G. 
Published: December 2004

AbstractThe retrograde, horseradish peroxidase technique has been used to demonstrate the cells of origin of corticofugal fiber systems arising in the rat somatic sensory cortex and projecting to the striatum, diencephalon, brainstem, and spinal cord. Correlative experiments conducted with the anterograde, autoradiographic method have been used to confirm the terminal distribution of many of these fiber systems. Corticofugal pathways directed to subcortical structures arise in the first and second somatic sensory areas exclusively from pyramidal cells of the infragranular layers, V and VI. Fibers which descend to the midbrain, pons, medulla and spinal cord arise exclusively from the largest pyramidal cells, the somata of which are found in the deep part of layer V (layer VB). There is some evidence for a sublaminar organization of the different classes of efferent cells within this layer. Fibers projecting to the diencephalon arise from somata situated throughout layer VI and to a lesser extent in layer V. Corticostriatal fibers arise only from cells with somata in layer V, but the somata are more superficially situated than those of the other classes of corticofugal neurons. The laminar distribution of the somata of corticofugal neurons differs considerably from that of commissural and ipsilateral corticocortical neurons.
Differential effects of monocular deprivation seen in different layers of the lateral geniculate nucleus
Authors: Casagrande V. A. , Guillery R. W. , Harting J. K. 
Published: December 2004

AbstractRecent investigations have suggested that the morphological effects of monocular deprivation can be explained by a developmental competitive interaction between the pathways from the two eyes. This study presents evidence in the tree shrew for binocular competition and for an unequal effect of such competition on the different layers of the lateral geniculate nucleus.The effects of monocular deprivation were evaluated by comparing cell size changes in the binocular and monocular segments of the lateral geniculate nucleus in three tree shrews raised with one eye sutured. In two of these animals the open eye was injected with 3H proline in order to identify accurately geniculate layers innervated by the non‐deprived eye. Cell sizes in three normal animals and one monocularly enucleated animal were measured for comparison.The results show the following main effects: First, that monocular deprivation significantly changes cell size in the binocular but not the monocular segment of the geniculate nucleus. Comparisons with cell size in normal animals indicates that non‐deprived cells may grow in response to deprivation. Second, that cell size in geniculate lamina 3 is not affected by monocular deprivation, suggesting that cells in this layer are morphologically or functionally secluded from competitive interactions affecting the other layers. Finally, that monocular enucleation in the adult tree shrew affects all parts of the geniculate nucleus including layer 3 and the monocular segment, demonstrating that these parts of the geniculate nucleus are responsive to lack of retinal innervation.
Anatomical and physiological localization of visual and infrared cell layers in tectum of pit vipers
Authors: Kass Leonard , Loop Michael S. , Hartline Peter H. 
Published: December 2004

AbstractVisual and infrared cell layers were identified in the tectum of the pit vipers crotalus viridis and Sistrurus melitus. Histologic reconstructions of 48 lesions utilizing the Prussian Blue technique were correlated with micrometer depth readings for 251 visual, infrared and bimodal single unit recordings. The visual cell layer extends caudally from approximately the level of the habenula to the rostral border of the posterior corpora quadrigemina. Neurons responding to visual stimulation are generally contained within zones 7b‐13, i.e., the superficial 600–700 μm of the optic tectum (stratum fibrosum et griseum superficial and the superficial sublayer of stratum griseum centrale). The infrared cell group is found in layer 7 (a and b; stratum griseum centrale) throughout the optic tectum. Eighty percent of the infrared neurons are found within 500–1,200 μm of the surface. In layer 7b the visual and infrared cell groups are mixed; bimodal neurons that respond to a combination of visual and infrared input are located predominantly in this sublamina. The lamination pattern for visual and nonvisual cell groups in the rattlesnake tectum appears to more closely resemble the colubrid tectum and mammalian superior colliculus than the tecta of other reptiles.
The development of the hippocampus and dentate gyrus in normal and reeler mice
Authors: Stanfield Brent B. , Cowan W. Maxwell 
Published: December 2004

AbstractThe histogenesis, the time of origin and the pattern of migration of the cells in the hippocampus and dentate gyrus, have been studies in normal and reeler mice.The earliest indication of a defect in the reeler hippocampus is seen on the fifteenth embryonic day (E15) which is at least 24 hours after the first indication of a defect in the neocortex. It is not until E18, that the dentate gyrus shows signs of its incipient abnormality. It appears then, in both the hippocampus and the dentate gyrus the gene defect first manifests itself at the stage at which the definitive cellular are assembled. Experiments involving the injection of 3(H‐TdR) at different developmental stages have confirmed that the site and rate of cellular proliferation in the reeler hippocampus and dentate gyrus are normal, as is the initial pattern of cell migration. However, in the reeler dentate gyrus, most postnatal cell proliferation occurs ectopically and in the hippocampus the normal “inside‐out” sequence of neurogenesis is reversed, the earliest pyramidal cells generated coming to lie superficially within the stratum pyramidale and the later formed cells being added at progressively deeper levels. There is no discernible gradient in the time of origin of the granule cells in the radial dimension of the reeler dentate gyrus, whereas there is an obvious “outside‐in” gradient in the normal animal. The characteristic gradients in cell proliferation seen in the transverse and longitudinal dimensions of the normal dentate gyrus are, however, also evident in the reeler mouse. Taken together, these observations suggest that the reeler gene exerts its effect on neuronal position only in the radial dimension, and does so at a stage of development subsequent to the proliferation and initial migration of the relevant neurons.Timm's sulfide silver preparations indicate that the characteristic staining patterns seen in the dentate gyrus and hippocampus appear at the same time, and mature at the same rate in normal and reeler mice.
Opening of tight junctions in cerebral endothelium. II. Effect of pressure‐pulse induced acute arterial hypertension
Authors: Nagy Zoltan , Mathieson Gordon , Hüttner Istvan 
Published: December 2004

AbstractAcute arterial hypertension was produced in male Wister rats by pressure pulse through the right internal carotid artery. The pressure pulse was induced by infusion of physiological saline as a bolus, at a rate of 0.63 ml per second by syringe pump. Evans blue (Eb) was used to visualize the areas of blood‐brain barrier opening. Intravenously injected horseradish peroxidase (HRP) was used to study the ultrastructural basis of permeability changes in cerebral endothelium. Eb outlined circumscribed areas of blood‐brain barrier opening. HRP extravasation was found mainly around small arteries. The capillary network was effected to a much lesser extent. Electron microscopy showed that HRP crossed the endothelial cell layer by intercellular routes. Glutaraldehyde fixed brain samples permeated with colloidal lanthanum supported these observations.