Food-taking in the cat investigated with transection of the rubro- and corticospinal tracts.

In cats with the distal paw shaved food-taking from a horizontally or vertically placed tube was recorded with a video camera, supplementary results were obtained with a high frequency video system. Measurements were made of the dorsal contour of the digits to investigate angular movement in the proximal interphalangeal (PIP) joint and withdrawal of the paw before and after complete transection of the rubro- and corticospinal tracts just rostral to the forelimb segments. In the preoperative state PIP flexion occurs before withdrawal of the paw in the large majority of cats. Postsurgically the main part of PIP flexion is made during withdrawal of the paw. It is suggested that PIP flexion before withdrawal allows for accurate manipulative placement of the digits on the target which depends on the rubro- and corticospinal tracts, while PIP flexion during withdrawal, which may favour speed at the expense of accuracy, can be made without the rubro-and corticospinal tracts.