Abstract
Effects of the posterior rhizotomy were studied on the conditioned leg flexion responses in dogs, paying special attention to whether the conditioned response was established by the classical procedure or by the instrumental one. The following results were obtained.
1. The classical conditioned response lost its preoperative high scores after the dorsal roots supplying the trained leg were completely sectioned.
2. The instrumental conditioned response suffered no detectable changes after the posterior rhizotomy.
3. A discussion was made concerning the role of afferent impulses in maintaining activity of the conditioned response.
