J.Jpn. Surg. Soc.. 54(10): 870-878, 1954

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Original article

A HISTOLOGICAL STUDY ON THE ARRANGEMENT OF CORTICAL MOTOR CENTERS

Through physiological researches, the motor centers are acknowledged as accumulations of points, and motor centers of each part in the cerebral cortex are believed to be entangled with each other in a mosaic arrangement. But decisive anatomical proof has as yet not been obtained. Therefore, the author has endeavored in this paper to substantiate this fact histologically. Dogs were used in this experiment. The object of the experiment is to study the arrangement of motor centers by means af causing retrograde degeneration in Betz's cells by excision of a portion of nerve fibersgerminating from cells of the cortical motor centers, at various heights in the cerebrum.
Through this experiment, the author reached to the conclusions as follows:
1. When excision of nerve fibers at the height of the subcortical region of motor centersis performed, the width of the "degenerated cell-field" was approximately equal to that of the portion excised, when nearest the cortex, and was distinctly degregated from "healthy cell-fields" on both sides.
The "mixed cell-field" consisting of degenerated cells and healthy cells was not acknowledged.
2. In the case of excision at the height of the medullary region, the width of the "degenerated cell-field" was more narrow than that of the portion excised, and on both sides of this field there were two "mixed cell-fields" having considerable width, and the external parts of them passed into "healthy cell-fields".
3. In the case of excision at the height of the internal capsule, there was no pure "degenerated cell-field". Only a "mixed cell-field" having considerable width, was found and on both sides of this "mixed cell-field" were "healthy cell-fields."
4. When the width of the portion excised is unified, in proportion to the increase of the "distance of the portion exeised from the cortex, the width of the dagenerated cell-fieId" decreased, and in the case of excision at the height of the internal capsule the "degenerated cell-field" was not found. The reverse is to be found in the "mixed cell-field," In the case of excision at the height of the subcortical region, there was no "mixed cell-field" appeared, while at the height of the internal capsule the "mixed cell-field" was most extensive.
5. Based upon these results the author concludes that the arrangement of motor centers in peripheral parts are of an entangled from, and insists on the revision of the concept describing a parallel and regular arrangement of motor centers generally accepted in the past.
(author's abstract)

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