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
URL:
http://dx.doi.org/10.1007/BF00234669
Permalink
