AUTHOR=Mari Stephen , Lecomte Charly G. , Merlet Angèle N. , Audet Johannie , Harnie Jonathan , Rybak Ilya A. , Prilutsky Boris I. , Frigon Alain TITLE=A sensory signal related to left-right symmetry modulates intra- and interlimb cutaneous reflexes during locomotion in intact cats JOURNAL=Frontiers in Systems Neuroscience VOLUME=17 YEAR=2023 URL=https://www.frontiersin.org/journals/systems-neuroscience/articles/10.3389/fnsys.2023.1199079 DOI=10.3389/fnsys.2023.1199079 ISSN=1662-5137 ABSTRACT=Introduction

During locomotion, cutaneous reflexes play an essential role in rapidly responding to an external perturbation, for example, to prevent a fall when the foot contacts an obstacle. In cats and humans, cutaneous reflexes involve all four limbs and are task- and phase modulated to generate functionally appropriate whole-body responses.

Methods

To assess task-dependent modulation of cutaneous interlimb reflexes, we electrically stimulated the superficial radial or superficial peroneal nerves in adult cats and recorded muscle activity in the four limbs during tied-belt (equal left-right speeds) and split-belt (different left-right speeds) locomotion.

Results

We show that the pattern of intra- and interlimb cutaneous reflexes in fore- and hindlimbs muscles and their phase-dependent modulation were conserved during tied-belt and split-belt locomotion. Short-latency cutaneous reflex responses to muscles of the stimulated limb were more likely to be evoked and phase-modulated when compared to muscles in the other limbs. In some muscles, the degree of reflex modulation was significantly reduced during split-belt locomotion compared to tied-belt conditions. Split-belt locomotion increased the step-by-step variability of left-right symmetry, particularly spatially.

Discussion

These results suggest that sensory signals related to left-right symmetry reduce cutaneous reflex modulation, potentially to avoid destabilizing an unstable pattern.