Fig. 5.

EMG recordings of treadmill-walking rats 40 d after lesion from two hindlimb muscles in rats with different locomotor scores. A, Only the recorded flexor muscle TA was found to be rhythmically active. In comparison with an uninjured rat (D), the contractions were prolonged and irregular, and the frequency was fairly low. The extensor muscle VL rarely shows activity. B, The extensor muscle VL is more active and bursts in a more rhythmic pattern. Cocontractions between the muscles occurred frequently. C, The flexor (TA) rhythm is increased, and the bursts are more defined and shorter. In addition, the extensor (VL) bursts are more regular and are well coordinated with the flexor muscle. D, Recordings of an intact control animal.