A new learning paradigm: adaptive changes in interlimb coordination during perturbed locomotion in decerebrate cats

Adaptive interlimb coordination was studied during perturbed locomotion in experimental chronically decerebrate cats. Perturbations were applied to the stance phases of the left forelimb using a newly developed treadmill which consisted of three compartments, one each for the left forelimb, the left hindlimb and both right limbs. During the perturbed locomotion, the treadmill belt for the left forelimb was driven at about twice the speed for the other limbs. During the first 1-50 perturbed steps, the step cycles of both forelimbs showed marked fluctuations; thereafter, the animals achieved stable locomotion by slightly shortening step cycle durations, and also by adjusting durations of bisupport phases asymmetrically in the left and right forelimbs. The present method provides a new test paradigm for adaptive interlimb coordination in locomotion, which will be useful in studying neural mechanisms of motor learning involving cerebellar synaptic plasticity.