Instrumental avoidance conditioning in the spinal rat.

Spinal rats exposed to an instrumental avoidance routine in a counterbalanced Horridge paradigm were able to achieve successively higher criteria. Both experimental and yoked control animals were capable of instrumental avoidance conditioning to incremental criteria; experimental animals exhibited retention of the task when tested. During acquisition, naive experimental animals were superior in performance to previous control animals. Due to the use of a counterbalanced Horridge paradigm, the effectsof sensitization and response variability are probably not sufficient to explain all of the results of this experiment. The data suggest that both graded acquisition and retention occur at the spinal level.