Locomotion-induced neural activity independent of auditory feedback in the mouse inferior colliculus.

Accumulating evidence indicates that the auditory system integrates movement-related signals with sensory input, yet the mechanisms across processing levels remain incompletely understood. The inferior colliculus (IC), a major midbrain integration center, exhibits locomotion-related neural activity, indicating that midbrain auditory neurons are sensitive to ongoing movement. However, their high sensitivity to sound makes it difficult to distinguish auditory feedback from other motor-related signals. To isolate non-auditory contributions, we recorded IC neural activity in deafened, head-fixed mice walking on a passive treadmill, eliminating auditory feedback through both air and bone conduction. Even in the absence of auditory input, IC neurons showed robust, bidirectional modulation during locomotion. Modulation often began before movement onset, even when aligned to electromyographic rather than treadmill signals, indicating both predictive and feedback components. These results demonstrate that non-auditory, movement-related signals significantly shape neural activity at the midbrain level, potentially supporting rapid, adaptive behavioral responses to sounds during locomotion.