Changes in cardiac conditioned reflexes in decorticate cats

Experiments were performed on 3 decorticate cats. Cardiac conditioned reflexes were developed by applying a combination of a 1000 c/s sound and the smell of ammonia vapor twenty or thirty times in succession. The reflex consisted in a decreased frequency of heartbeat in response to the conditioned signal alone. The elaborated conditioned reflexes were stable, and were maintained even after a three-month interval. It was possible to establish a crude differential response in the decorticate animals. In one hemidecorticate animal, the conditioned reflex established was maintained when the second hemisphere was removed.