MODIFICATION OF LEG FLEXION IN RESPONSE TO REPEATED STIMULATION IN A SPINAL AMPHIBIAN (XENOPUS-MULLEREI)

Summaryo1.Experiments were conducted on spinal toads (Xenopus mullerei). Each animal was suspended vertically, its legs hanging downward. The animal was left until its lowest toe remained at its lowest (rest) position for at least 5 min.2.The foot was then stimulated (either mechanically or electrically) whenever the lowest toe fell below a fixed (set) position.3.The interval between stimuli increased when the set position was 4 mm and 8 mm above rest position. There was no significant increase in the interstimulus interval when the set position was 12 mm above rest position.4.During an experiment the foot was held for progressively longer periods of time in the vicinity of the set position.5.Various control experiments indicated that the experiments described in paragraphs 3 and 4 above were not a simple consequence of repeatedly stimulating the leg. These effects were not observed in the frog. © 1969.