bluuebunny/crossref_metadata_2025_split huggingface dataset:
Direct projection from the dorsal lateral geniculate nucleus to the prestriate cortex in macaque monkeys
Authors: Yukie Masao , Iwai Eiichi 
Published: January 2005

AbstractThe enzyme horseradish peroxidase (HRP) was separately injected into striate, prestriate, inferotemporal, and parietal cortices in 19 macaque monkeys, and the lateral geniculate nucleus (LGN) was examined for retrograde transport. Labeled LGN cells were identified only in the animals with HRP injections into the striate and prestriate cortex. Following injections into either of these regions, labeled cells were found in both parvocellular and magnocellular regions of the ipsilateral LGN only, in keeping with the topographic relation of HRP injection sites in the cortex to labeled areas in the LGN. It was also found that (1) labeled LGN cells were less numerous in both laminar and interlaminar zones following HRP injection into the prestriate cortex, whereas following HRP injection into the striate cortex labeled cells were found almost exclusively in the laminae, and localized to a wedge‐shaped region; (2) following HRP injection into the prestriate cortex, the mean sizes of the labeled parvocellular and magnocellular cells, estimated in projected diameter, were almost the same, these means being significantly larger than the mean size of labeled parvocellular cells and much smaller than that of labeled magnocellular cells following HRP injection into the striate cortex; (3) the shapes of the labeled LGN cells following HRP injection into the prestriate cortex were ovoid, fusiform, or triangular (or multipolar), whereas those following HRP injection into the striate cortex were uniformly ovoid or round. The above findings following HRP injections into the prestriate cortex in normal monkeys were confirmed by HRP injections into the prestriate cortex of monkeys whose striate cortex had been removed several months prior to the injection; labeled cells were found in the confines of areas of retrograde degeneration in the LGN and their labeling pattern was the same as that in intact animals. It was concluded that in macaque monkeys, just as in the cat, a geniculoprestriate projection system exists; it was suggested that there are two parallel systems of visual information processing from the LGN to the prestriate cortex, a direct one and an indirect one through the striate cortex.
Physiological and anatomical evidence for a discontinuous representation of the trunk in S‐I of tree shrews
Authors: Sur Mriganka , Weller Rosalyn E. , Kaas Jon H. 
Published: January 2005

AbstractMicroelectrode mapping methods revealed that the representation of the body surface in the first somatosensory area of cortex, S‐I, of the tree shrew is unique in that only the ventral trunk was found in the usual location of the trunk representation in cortex of the dorsolateral surface of the cerebral hemisphere. Instead, the dorsal trunk was found as an extension of the representation of the posterior leg in cortex on the medial wall. The separation of the representation of the trunk occurs along a line that is counter to the orientation of the dorsal root dermatomes, so that S‐I of the tree shrew clearly cannot be characterized as a serial representation of dermatomes. Anatomical studies of connections support the conclusion that the representation of the trunk is split in S‐I. Both the representation of the dorsal trunk on the medial wall of the cerebral hemisphere and S‐I of the dorsolateral surface were found to project to S‐II when horseradish peroxidase was injected into S‐II.
Morphology of radial glia, ependymal cells, and periventricular neurons in the optic tectum of goldfish (Carassius auratus)
Authors: Stevenson James A. , Yoon Myong G. 
Published: January 2005

AbstractThere are three populations of cells in the deep layers of the optic tectum in a normal adult goldfish: the periventricular neurons, the ependymal cells, and the radial glia. The characteristic morphological features which distinguish the three cell populations are examined at light and electron microscopic levels in the present work.A radial glial cell has a deeply invaginated nucleus located in a subependymal layer. Its cytoplasm contains mitochondria with 35‐nm dark granules and 20‐nm microtubules but no intermediate filaments. Its prominent radial process extends through the superficial tectal layers. In contrast, the processes of an ependymal cell ramify and interweave within the ependymal region. The cytoplasm of an ependymal cell contains prominent bundles of intermediate filaments but no microtubules. Its soma lies at or near the ventricular surface. A periventricular neuron has a round nucleus and a smooth dendrite which extends toward the superficial tectal layers. Its cytoplasm contains microtubules and agranular mitochondria. Axosomatic and axodendritic synapses are found on periventricular neurons.The morphological characteristics of these cell types are considered in relation to previous descriptions of teleost tectal cytology and with regard to the atypical natures of the cytoskeletal elements of the ependymal and radial glial cells.
The effect of neonatal 6‐hydroxydopamine treatment on synaptogenesis in the visual cortex of the rat
Authors: Blue Mary E. , Parnavelas John G. 
Published: January 2005

AbstractIt has been proposed repeatedly that the noradrenergic (NE) system may exert an influence on cortical development. We have tested this proposition by examining synaptogenesis in the visual cortex of rats whose NE afferents were selectively lesioned by injections of the neurotoxin 6‐hy‐droxydopamine (6‐OHDA). Control littermates were injected with equal volumes of vehicle. Montages of electron micrographs covering approximately 50 μm‐wide strips of cortex were assembed from both groups of animals at 2,4,6,8,14, and 90 days of age. Symapses counts revealed a significantly higher density of synapses in the cortex of 6‐OHDA‐treated rats during the first week of postnatal life. The difference between the experimental and control rats was less apparent during the second postnatal week, and at day 90 the densities of synapses were similar for the two groups of animals. The enhanced density, which was the result of the increased number of Gray's type I synapses, was confined to the subplate region at day 2 but became more widespread in the cortex at subsequent stages of development. From these observations it would appear that the NE system exerts an inhibitory influence on synapse formation in the visual cortex in early postnatal life.
The island of Calleja complex of rat basal forebrain. I. Light and electron microscopic observations
Authors: Ribak Charles E. , Fallon James H. 
Published: January 2005

AbstractAn analysis of the cells and their processes within the island of Calleja complexes (ICC) was made in light and electron microscopic preparations to determine synaptic relationships within this part of the basal forebrain. The light microscopic preparations showed that the ICC contained two cell types, granule cells and large cells. In electron microscopic preparations, the somata of granule cells were grouped together and were directly apposed to other somata of granule cells. Specialized junctions (4–6 nm wide) that occurred at sites of somal apposition suggested ephaptic coupling of granule cells. The granule cell somata had nuclei that contained clumps of heterochromatin adjacent to smooth nuclear envelopes. The perikaryal cytoplasm of these cells consisted of a relatively thin rim containing few organelles. Spinous dendrites of small diameter were occasionally found in continuity with these cells. Axon terminals rarely formed synapses with the somata of granule cells, but were more frequently found to synapse on their dendrites and dendritic spines. These features for granule cells are similar to those for medium‐sized spiny neurons in the neostriatum.The somata of the large cells were found either within the core or along the dorsal margin of the ICC. The large cells had infolded nuclei and an abundant perikaryal cytoplasm that contained many organelles. Large diameter dendrites that tapered down to smaller diameters emanated in many directions from these somata. Axon terminals covered nearly the entire surface of these somata and dendrites where they commonly formed symmetric synaptic junctions. These characteristics of large cells indicate a resemblance to the large cells in the globus pallidus and ventral pallidum. Therefore, the ICC have ultrastructural features found in both the neostriatum and globus pallidus.
Guidance of neuritic growth in the transverse plane of embryonic mouse spinal cord
Authors: Holley John A. , Nornes Howard O. , Morita Michio 
Published: January 2005

AbstractThe development of cytoarchitecture in the lumbar spinal cord of mouse embryo between embryonic day 13 (E13) and E15 was studied by scanning and transmission electron microscopy. A pattern of two perpendicularly oriented sets of cellular elements was found in the intermediate zone at both E13 and E14. One set consisted of radially oriented processes that often originated from cell bodies in the ventricular zone. The second set consisted of cell bodies and processes that were oriented predominantly parallel to the neural tube margin and in the transverse plane. This set was termed circumferential elements and included most of the immature neurons. At E13, the circumferentially oriented cells were arranged into rostrocaudally compressed sheets or layers that were partially segregated one from another by flattened bundles of radially oriented processes. This pattern of orthogonally arranged circumferential and radial elements remained evident through E14 when the profuse growth of cellular processes began to obscure the identity of individual cells seen on the scanned surface. The exposed intermediate zone surface at E14 and E15 often had relatively flat transverse areas separated by ledges of broken tissues, indicating that most neurites grow in the transverse plane. These observations indicate that the sequential patterned development of an organized morphological substratum is an important factor in orienting neurite growth.
Topographic organization of the brainstem afferents to the mediodorsal thalamic nucleus
Authors: Velayos José Luis , Reinoso‐Suarez Fernando 
Published: January 2005

AbstractThe afferent projections from the brainstem to the mediodorsal thalamic nucleus (MD) were studied in the cat, by means of retrograde transport of horseradish peroxidase. A topographical arrangement of these projections is described. The medial part of MD is the area of the nucleus which receives fewer afferents from the brainstem. After injections in this part, labeled neurons were observed mainly in the interpeduncular nucleus, the ventral tegmental area and the substantia nigra. After injections of HRP in the intermediate part of the MD, labeled cells were seen mainly in the interpeduncular nucleus, substantia nigra, dorsal and centralis superior raphe nuclei, dorsal tegmental nucleus, and coeruleus complex. Less conspicuous was the number of labeled cells in the central gray and the dorsolateral portion of the tegmentum of the mesencephalon and pons. After injections in the lateral part of MD, labeled neurons were observed mainly in the deep layers of the superior colliculus, central gray, the oral paramedian pontine reticular tegmentum, and the interpeduncular nucleus. Labeled cells were also observed in the substantia nigra, locus coeruleus, dorsal tegmental nucleus, cuneiform area, and the mesencephalic reticular formation. These findings show the MD as a thalamic link of three different groups of brainstem structures projecting to different cortical areas with different functional significance.
Connections of the octopus optic lobe: An HRP study
Authors: Saidel William M. 
Published: January 2005

AbstractThe major visual centers of the octopus central nervous system are the paired optic lobes. Bidirectional transport of horseradish peroxidase (HRP) was used to determine connections of the optic lobe. Cells afferent to the optic lobe were identified by retrograde HRP transport in the following lobes of the central ganglia: anterior basal, median basal, dorsal basal, interbasal, subvertical, precommissural, brachial, and magnocellular. Labeled cells were also observed within the contralateral optic lobe, various optic tract lobes bilaterally, and in photoreceptors of the ipsilateral retina. Additionally, individual fibers, in part originating from cells in the posterior subvertical lobe, were labeled within the central neuropil core of various vertical lobules. Differences in results between superficial and deep optic lobe medulla injections indicate that some afferent projections from central sources may terminate on cell populations at specific depths within the lobe.Efferent optic lobe fibers into the superior frontal and lateral basal lobes were labeled by anterograde transport. Other possible optic lobe efferent projections terminated in supraesophageal lobes and the magnocellular lobe.The many inputs to the optic lobe from higher motor and associative centers in the central ganglia emphasize that the medulla region of the optic lobe is an exceptionally complex integrative area.
Alterations of the crossed parabigeminotectal projection induced by neonatal eye removal in rats
Authors: Stevenson James A. , Lund Raymond D. 
Published: January 2005

AbstractProjections of the parabigeminal nucleus to the contralateral superior colliculus and dorsal lateral geniculate nucleus were examined in normal adult pigmented rats and in adult rats from which one or both eyes had been removed at birth. In normal rats the crossed parabigeminotectal projection is restricted to the superficial layers in anterior and medial areas of colliculus, regions innervated also by the lower temporal portion of the ipsilateral retina. In unilaterally enucleated animals the crossed parabigeminotectal projection to the “denervated” colliculus is expanded, as is the retinal projection from the ipsilateral eye. In addition, there is acrossed parabigeminal projection to the “denervated” dorsal lateral geniculate nucleus in these rats. In bilaterally enucleated animals the parabigeminotectal projection is expanded, but not as greatly as in unilateral enucleation cases; there is a crossed parabigeminothalamic projectionin these animals as well.The corresponding termination patterns of the contralateral parabigeminal nucleus and the ipsilateral retina in the normal superior colliculus mayindicate a functional and/or developmental interdependence between the projections from these two regions. The existence of an expanded parabigeminotectal projection in bilaterally enucleated rats shows that a sustained ipsilateral retinotectal projection is not necessary for the establishment of a crossed parabigeminotectal projection, but points to the possibility that ipsilateral retinal input may constrain the parabigeminal projection to terminate within certain boundaries. The even greater expansion of the projection from the parabigeminal nucleus to the colliculus which receives an expanded projection from the ipsilateral retina of unilaterally enucleated rats suggests that the functional organization of the ipsilateral retinotectal projection may be capable of restricting the size of the terminal field of the crossed parabigeminotectal projection.
Innervation of avian latissimus dorsi muscles and axonal outgrowth pattern in the posterior latissimus dorsi motor nerve during embryonic development
Authors: Bourgeois Jean‐Pierre , Toutant Madeleine 
Published: January 2005

AbstractThe distribution of the innervation to the anterior latissimus dorsi (ALD) and posterior latissimus dorsi (PLD) muscles of the chicken are described on the day of hatching and 6 weeks later using electron microscopy. In the ALD muscle, there are 5,000 muscle fibres and 374,400 endplates supplied by about 169 skeletomotor axons; in the PLD muscle, there are 12,000 focally innervated muscle fibers supplied by about 20 skeletomotor axons. On the cell surface of the muscle fibers the mean total subsynaptic area contacted by each motor axon is comparable in the ALD and PLD muscles. The growth pattern of the axons in the PLD motor nerve was described from the ninth day in ovo up to 6 weeks after hatching. The axons arrive in the PLD muscle in two successive waves: first, the large somatic axons which are already present before the ninth day in ovo and second, the small autonomic axons which continue to accumulate until hatching. The total number of somatic axons decreases from the ninth day until the hatching day when it reaches its definitive value. This decrease takes place during a period when the numbers of myofibers and of endplates dramatically increase, and it coincides with the axonal segregation by the Schwann cells. The myelination of the axons starts on the 15th day in ovo and is essentially complete upon hatching.Despite the decreasing number of somatic axons in the PLD nerve, the decrease in number of nerve endings per PLD endplate and the increasing number of PLD endplates per PLD muscle, it was found that between the 16th day in ovo and 6 weeks after hatching the mean number of axonal branches per PLD motor axon does not decrease.
Enkephalin‐mediated basal ganglia influences over the optic tectum: Immunohistochemistry of the tectum and the lateral spiriform nucleus in pigeon
Authors: Reiner Anton , Karten Harvey J. , Brecha Nicholas C. 
Published: January 2005

AbstractBy using immunohistochemical techniques with antisera directed against either leucine‐enkephalin or methionine‐enkephalin (generously supplied by K. ‐J. Chang), four distinct bands of fibers with enkephalinlike immunoreactivity were demonstrated in the pigeon tectum: (1) a thin band of thick fibers and tightly clustered bulbous swellings in layer 3, (2) a broader band of fibers with less tightly clustered bulbous swellings in layer 5, (3) a broad band of numerous obliquely and radially oriented fibers that spanned layers 8–13, and (4) a band of sinuous fibers in layer 15. In addition, numerous enkephalinergic cell bodies with radially ascending processes were seen in layers 8–10. Since the neurons of the avian lateral spiriform nucleus (SpL) of the pretectum are known to contain enkephalin (Davis et al., 1980; De Lanerolle et al., 1981) and project to the tectum (Brecha et al., 1976; Reiner et al., 1982), unilateral electrolytic lesions were made of SpL. In birds with unilateral lesions of SpL, layers 8–13 of the ipsilateral tectum were nearly devoid of enkephalinergic fibers, but no alterations were seen in layers 3, 5, and 15. Since no other neurons in the vicinity of SpL are enkephalinergic and project to the tectum, the loss of enkephalin‐immunoreactive fibers in the ipsilateral tectal layers 8–13 is attributable to the destruction of SpL. Although the source of the enkephalinergic fibers in tectal layers 3, 5, and 15 is unclear, part of the enkephalin pattern in layers 3 and 5 may derive from the ascending processes of the enkephalinergic neurons of layer 8–10. The present results indicate that SpL has an enkephalinergic projection to layers 8–13 of the ipsilateral tectum. The avian SpL receives its major input from the ascending processes of the enkephalinergic neurons of layers 8–10. nuclei that themselves receive major basal ganglia inputs (Reiner et al., 1982), and projects to the tectal layers 8–13 (Reiner et al., 1982), the layers of origin of the major tectal efferent projections (Reiner and Karten, 1982). The enkephalinergic fibers in layers 8–13 may, thus, have some influence upon the motor output functions of the avian tectum.
Spinocerebellar projections to lobules III to V of the anterior lobe in the cat, as studied by retrograde transport of horseradish peroxidase
Authors: Matsushita Matsuo , Hosoya Yasuhiko 
Published: January 2005

AbstractSpinocerebellar tract (SCT) neurons projecting to lobules III to V of the cerebellar anterior lobe were identified by the retrograde horseradish peroxidase technique.SCT neurons projecting to lobule III with crossed ascending axons were located mainly in the central cervical nucleus (CCN), the medial part of lamina VII of L6 to the caudal segments, and the dorsal horn (lamina V) and ventral horn (lamina VIII) of the sacral‐caudal segments. Spinal border cells with crossed ascending axons also projected to lobule III. SCT neurons projecting to this lobule with uncrossed ascending axons were located in the medial part of lamina VI of the cervical segments and the middle part of lamina VII of C6 to T1, lamina V of the lower cervical, thoracic and the lumbar segments, Clarke's column including marginal neurons, and the medial part of lamina VI of L5 and L6. These neuronal groups also projected to lobule IV, except for those present caudal to L6 (in the medial part of lamina VII, and laminae V and VIII of the sacral‐caudal segments). A far smaller number of similar neurons projected to lobule V.Injections of HRP restricted to the vermal region labeled mainly neurons in the CCN and Clarke's column while restricted injections to the intermediate‐lateral regions labeled ipsilaterally spinal border cells, lamina V neurons, and Clarke column neurons, especially of the lumbar segments as well as marginal neurons of this column.
The corticopontine system in the rat. I. Mapping of corticopontine neurons
Authors: Wiesendanger R. , Wiesendanger M. 
Published: January 2005

AbstractThe expanse of cerebral cortex containing corticopontine neurons was explored in rats. The retrograde tracer horseradish peroxidase (HRP) was iontophoresed into subdivisions of the pontine nuclei (PN). The densest projection was seen to originate from somatosensory and motor areas. Visual areas also provide a major contingent of corticopontine neurons, whereas auditory areas appear to have only a minor projection. Consistent labeling of cells was also seen in the granular cingulate cortex, especially in the junction region of anterior and posterior cingulate cortex. This and a sparse projection from dorsal and posterior “insular” cortex (rhinal sulcus) have not been described in detail in previous studies.
Neuropeptide immunoreactivity in Limulus. I. Substance p‐like immunoreactivity in the lateral eye and protocerebrum
Authors: Chamberlain Steven C. , Engbretson Gustav A. 
Published: January 2005

AbstractSubstance P‐like immunoreactivity was examined in the Limulus lateral eye and protocerebrum by the unlabeled antibody peroxidase‐antiperoxidase method. Small‐diameter immunoreactive fibers innervate the corneal epidermis of the lateral eye and appear to be part of a generalized epidermal innervation. No immunoreactive neurons or fibers were found in the ventral, median, or lateral optic nerves nor in the lamina or chiasma. The optic medulla contains neurons with immunoreactive perinuclear caps in the ganglion cell layer and fibers of undetermined origin in the posterolateral regions of the neuropil. The central body contains many immunoreactive fibers in its neuropil, some or all of which arise from neurons adjacent to its anteromedial tips. Immunoreactive neurons within the curve of the central body give rise to processes which join the central neuropil of the protocerebrum. The immunoreactive innervation of the corpora pedunculata includes processes which terminate among Kenyon cell somata, and processes in the peduncular neuropil, all of which arise from a bilateral cluster of neurons along the midline. Attempts to investigate the source of the immunoreactive fibers using cobalt impregnation of the severed circumesophageal connective have revealed two additional innervations of the corpora pedunculata, one from raphe neurons along the midline and one from lateral portions of the midline ganglion adjacent to but separate from that portion containing the immunoreactive neurons. The results demonstrate that immunocytochemical methods are another powerful tool for the study of neuronal pathways in invertebrates.