Error signals driving locomotor adaptation: cutaneous feedback from the foot is used to adapt movement during perturbed walking

摘要

Locomotor patterns must be adapted to external forces encountered during daily activities. The contribution of different sensory inputs to detecting perturbations and adapting movements during walking is unclear. In the present study, we examined the role of cutaneous feedback in adapting walking patterns to force perturbations. Forces were applied to the ankle joint during the early swing phase using an electrohydraulic ankle-foot orthosis. Repetitive 80Hz electrical stimulation was applied to disrupt cutaneous feedback from the superficial peroneal nerve (foot dorsum) and medial plantar nerve (foot sole) during walking (Choi etal. 2013). Sensory tests were performed to measure the cutaneous touch threshold and perceptual threshold of force perturbations. Ankle movement were measured when the subjects walked on the treadmill over three periods: baseline (1min), adaptation (1min) and post-adaptation (3min). Subjects (n=10) showed increased touch thresholds measured with Von Frey monofilaments and increased force perception thresholds with stimulation. Stimulation reduced the magnitude of walking adaptation to force perturbation. In addition, we compared the effects of interrupting cutaneous feedback using anaesthesia (n=5) instead of repetitive nerve stimulation. Foot anaesthesia reduced ankle adaptation to external force perturbations during walking. The results of the present study suggest that cutaneous input plays a role in force perception, and may contribute to the error' signal involved in driving walking adaptation when there is a mismatch between expected and actual force.