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  • 1970-1974  (2)
  • 1950-1954  (2)
  • Polymer and Materials Science  (2)
  • Conduction velocity  (1)
  • Motor cortex  (1)
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Years
Year
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 17 (1973), S. 315-332 
    ISSN: 1432-1106
    Keywords: Red nucleus ; Unit recording ; Motor cortex ; Topographical organization ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A topographical study of the cortico-rubrospinal pathway was conducted in cats anesthetized with chloralose. Extracellular unit recordings were made from cells in the red nucleus projecting to the spinal cord. They were identified by antidromic invasion following stimulation of their axones at the 2nd cervical and 9th thoracic levels of the spinal cord. I. The pericruciate cortical regions from which spikes could be induced in rubrospinal neurons were limited to the lateral part of the anterior sigmoid gyrus, the lateral sigmoid gyrus and the anterior part of the posterior sigmoid gyrus. No responses were obtained from stimulation of the medial part of the anterior sigmoid gyrus or the gyrus proreus. Compared to the somatotopic organization of the motor cortex for the cat described by Woolsey (1958), our results show that the rubrospinal cells receive projections from the motor cortex controlling proximal and distal muscles but not axial muscles. II. Neurons projecting to the cervico-thoracic cord receive afferents from the lateral part of the anterior sigmoid gyrus and the lateral sigmoid gyrus whereas those projecting to the lumbo-sacral cord receive projections from the entire surface of the sigmoid gyrus except the medial part of the anterior sigmoid gyrus and the gyrus proreus. III. A latero-medial organization of cells within the red nucleus was found according to the origin of their cortical afferents. Rubrospinal neurons with fibers terminating in the cervical or thoracic cord receive projections from the motor cortex controlling the proximal musculature of the forelimb when they are located in the dorso-lateral region of the nucleus and the entire forelimb motor cortex when they are located in the medial part of the nucleus. It is suggested that this organization may indicate a control of proximal forelimb musculature by dorsolateral rubrospinal cells and distal musculature by medial cells. IV. Rubrospinal cells placed medially in the nucleus receive more convergent projections (i.e. from a greater cortical surface) than cells placed more laterally. It was shown that for certain cells the convergence occurs in the direct pathway. These results are discussed in terms of a functional organization allowing coordinated movements of different segments of a single limb or of different limbs.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 14 (1972), S. 363-371 
    ISSN: 1432-1106
    Keywords: Rubrospinal cells ; Unit recording ; Topographical organization ; Conduction velocity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Mapping of cells at the origin of the rubrospinal tract was conducted in the cat. 1. Rubrospinal neurons sending efferents to cervico-thoracic segments of the spinal cord are located in the dorso-medial part of the nucleus. These neurons are especially medial in the caudal planes and especially dorsal in the rostral planes. Neurons with efferents terminating at the level of lumbo-sacral segments of the cord occupy the ventro-lateral part of the nucleus. These neurons are especially lateral in the caudal planes and especially ventral in the rostral planes. The limit between these two cell populations is clear in the caudal and middle thirds of the nucleus but considerable overlap is seen in the rostral third. These results agree with the anatomical findings of Pompeiano and Brodal (1957). 2. For the population of lumbar neurons the conduction velocities ranged from 31 m/sec to more than 120 m/sec with a mean of 85 m/sec. 3. Rubrospinal cells are found throughout the nucleus. The most caudal planes are essentially composed of cells with rapidly conducting fibers whereas in the middle and rostral planes a cell population with increasingly slower conducting fibers appears. The results of the present study are discussed in relation to classical data on the magnocellular and parvocellular divisions of the red nucleus. 2.The third author acknowledge the personal support of the Medical Research Council of Canada.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 5 (1950), S. 737-738 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Off-meridian small-angle x-ray interference maxima and multiple orders of small-angle interference maxima have been observed for certain synthetic high polymer fibers including polythene, polyamides, polyethylene terephthalate, and polyvinyl alcohol. The observations indicate that the ordering of the structures responsible for small-angle diffraction may be two- or three-dimensional rather than one-dimensional and that such ordering must extend over larger volumes of space than previously published data would indicate. The fibers must be given relaxation treatments to form the structures that result in small-angle maxima except for polythene in which they appear merely on orientation. The relaxation treatments increase the crystallite size as shown by large-angle pictures and modify the positions and shapes of the small-angle maxima. An increase in the degree of relaxation increases the intensity of the interference and increases the magnitude of the interplanar spacing except for polyvinyl alcohol, in which the interplanar spacing is not affected. Samples of 66 nylon, which varied in molecular weight from 26,000 to 200,000 gave identical small-angle interference patterns within the limits of accuracy.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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