Dependence of Respiratory Reaction on the Intensity of Locomotor Response to Transcutaneous Electrical Stimulation of the Spinal Cord

Abstract

We have studied the reaction of the respiratory system to transcutaneous spinal cord stimulation inducing stepping movements of large and small amplitudes. We have shown that the small amplitude of the generated stepping movements was associated with a reduction of the tidal volume, and generated movements with a large amplitude resulted in the elevation of the expiratory flow. We have compared the reactions of the respiratory system during stepping movements induced by spinal cord stimulation and by voluntary efforts. It has been found that, during stepping movements induced by the spinal cord stimulation, lung ventilation increased through reduction of the inspiration and expiration times, while the expiratory flow increased. During voluntary stepping movements, the inspiration time decreased, while the inspiratory and expiratory flows increased. These effects can ensue from tonic activation of abdominal muscles, as well as from the summation of the effects of spinal stimulation and working hyperpnoea.