Modular organization of the murine locomotor pattern in presence and absence of sensory feedback from muscle spindles

Locomotion on land and in water requires the coordination of a great number of muscle activations and joint movements. Constant feedback about the position of own body parts in relation to the surrounding environment and the body itself (proprioception) is required to maintain stability and avoid failure. The theory of muscle synergies states that the central nervous system might control muscles in orchestrated groups (synergies) rather than individually. We used this concept on genetically modified mice, lacking one class of proprioceptors. Our results provide evidence that proprioceptive feedback is required by the central nervous system to accurately tune the modular organization of locomotion.