The pyramidal tract in the cat, dog and monkey / by Sutherland Simpson.
- Sutherland Simpson
- Date:
- [1906?]
Licence: In copyright
Credit: The pyramidal tract in the cat, dog and monkey / by Sutherland Simpson. Source: Wellcome Collection.
Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.
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![lesions may, as pointed out by Schafer (78), be due to slight unavoidable injury to other parts of the hemisphere, or to altered mechanical or vascular conditions produced by the operation, and when these conditions return to the normal, the sensory paralysis passes off, while the motor remains. They may, however, have a more far-reaching cause, as is shown by the fact that they are often accompanied by hemianopsia. This has been recorded by Mott, and by Ferrier and Turner, and has recently been emphasised by Hitzig. 2. Anatomical.—In the cat, as the result of a lesion cutting off the whole left motor cortex, degeneration -was found in the internal capsule of the same side, occupying about the middle three-fifths of its whole extent, the anterior and posterior (superior and inferior in the cat) extremities being free. [In only two cats were sections made through the internal capsule and thalamencephalon.] Degenerated fibres were found passing from the centrum ovale through the corpus callosum to the right hemisphere, but none were seen to turn down into the right internal capsule. Opposite the posterior part of the left optic thalamus some fibres leave the capsule, the bundles of which are at this level becoming compacted together to form the crusta, and passing into the grey matter of this and the subthalamic region appear to end there, as indicated by the presence of a considerable quantity of fine or terminal degenera- tion. In the upper levels of the mesencephalon the whole of the left crusta is degenerated, with the exception of a narrow marginal area along its antero-lateral border. From the posterior aspect of the crusta numerous degenerated fibres pass backwards through the substantia nigra into and through the tegmentum, towards the anterior corpus quadrigeminum of the same side. These for the most part end in the grey matter of that body, but a few curve round close to its posterior or superior surface, and crossing in the roof of the aqueduct, are lost in the quadri- geminal body of the opposite side. In only one or two cases were any fibres seen to enter the central grey matter around the Sylvian aqueduct, and these did not appear to end there, but seemed to be continued through the lateral portion of it in their course towards the anterior corpus quadrigeminum. In every case there was a varying amount of fine degeneration](https://iiif.wellcomecollection.org/image/b22470918_0048.jp2/full/800%2C/0/default.jpg)
