Effects of corticospinal lesions upon treadmill locomotion by cats.

We studied the pattern of stepping in cats, before and after the placement of lesions in the corticospinal system. We found a deficit after the lesions, which was characterized by increased extension of the involved hindlimbs during the stance (E2--E3) phase of the step cycle. This deficit lasted two weeks or less. It may reflect loss of inhibitory influences upon extensor motoneuron pools.