Evidence for spinal conditioning in intact rats.

Prior work suggests that spinal systems are sensitive to the stimulus relationships that underlie Pavlovian conditioning. We studied this phenomenon in Sprague-Dawley rats by pairing a vibrotactile conditioned stimulus (CS) with a tailshock unconditioned stimulus (US). Experiment 1 showed that spinal rats exhibit differential conditioning, having longer tail-flick latencies on the tail-flick test during a CS that was paired with the US (conditioned antinociception). Experiment 2 showed that rats trained with the cord intact still exhibit differential conditioning after the cord is cut. This suggests that spinal learning contributes to behavioral plasticity in intact subjects.