Differential role of spinal and supraspinal processing of proprioceptive information in mouse locomotion

Abstract

Robust locomotion relies on information from proprioceptors: sensory organs that communicate the position of body parts to the spinal cord and brain. Proprioceptive circuits in the spinal cord are known to regulate locomotion in challenging environments. Yet, the regulatory importance of the brain remains less clear. Here, through mouse genetic studies and in vivo electrophysiology, we examined the role of the brain in integrating proprioceptive information during locomotion. The systemic removal of proprioceptors left the animals in a constantly perturbed state, similar to that observed during mechanically perturbed locomotion in wild type and characterised by longer and less accurate activation patterns. In contrast, after surgically interrupting the ascending proprioceptive projection to the brain through the dorsal column pathway, wild-type mice showed normal walking behaviour, but lost the ability to respond to external perturbations. Our findings provide direct evidence of a pivotal role for ascending proprioceptive information in achieving safe locomotion.