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  • 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 60 (1985), S. 411-416 
    ISSN: 1432-1106
    Keywords: Vision ; Motion after-effects ; Cat ; Visual cortex
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Responses of striate cortical neurones to bars of optimal orientation and width, moving with fixed velocity, were recorded in the lightly anaesthetized cat. Effects of periods of pre-adaptation with square-wave gratings of variable spatial frequency and velocity, drifting continuously in each cell's preferred or null directions, were investigated. Variations of cells' directional bias and responsiveness to oriented bars were assessed in relation to the degree and time-course of pre-adaptation to drifting gratings, compared with the preceding level of firing when exposed to uniform backgrounds of the same average luminance. All cells showed some susceptibility to pre-adapting moving gratings: subsequent responses to a bar were initially depressed in the direction of pre-adaptation and, in direction-biased or bidirectional cells, were enhanced in the opposite direction, compared with bar responses following exposure merely to a uniform background. These effects were strongest and most consistent amongst standard complex cells and weakest amongst special complex cells: maximal effects were obtained with adapting gratings of optimal velocity and spatial frequency.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 86 (1991), S. 324-332 
    ISSN: 1432-1106
    Keywords: Vision ; Optokinetic nystagmus ; Eye movements ; Plaids ; Brainstem ; Motion perception ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We have recorded the direction of optokinetic nystagmus (OKN) elicited by moving plaid patterns in order to dissociate the pathways that mediate horizontal OKN. The plaids used comprised two drifting sinusoidal gratings arranged such that their individual directions of drift were very different from the direction of coherent motion of the overall pattern. The direction of OKN with binocular viewing was close to the mean of the component directions, suggesting a dominant influence of cortical visual neurons that respond to oriented one-dimensional components of the image. But the direction of OKN was consistently shifted slightly towards the direction of motion of the overall pattern, suggesting a secondary influence responsive to pattern direction. OKN recordings obtained during monocular viewing suggest that this secondary influence reflects the direct retinal pathway to the brainstem structures mediating OKN.
    Type of Medium: Electronic Resource
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