抄録
Following the various lesions in the cerebral cortex of the monkeys, the degenerated fibers were traced in the level of the cerebral peduncle, pons and pyramid of the medulla oblongata. Extensive intermingling of the projection fields is demonstrated at the cerebral peduncle but there is a denser aggregation of the face fibers toward the medial side, arm fibers in the middle and foot fibers toward the lateral side of the middle 3/5 of the cerebral peduncle.
The parietopontine tract passes at the lateral 2/5 of the pes pedunculi. In the pons, the parietopontine tract is rather concentrated in the dorso-lateral groups of the longitudinally descending bundles. Otherwise further extensive intermingling of the fibers occurs in the pontine level and no clear cut somatotopographical pattern is found.
In the medullary pyramid, the degenerated fibers are diffusely and homogenously distributed. Small numbers of fibers in the motor face lesion still descend beyond the medullary pyramid. It was found that the pyramidal tract fibers were not clearly demarcated topographically in the brain stem as described in the diagram of some literatures.
