Walking Selectively Modulates Behaviorally Relevant Auditory Responses According to Stride Cycle Phase
Perception in natural environments unfolds while the body is in motion, yet how locomotion shapes cortical computations for fine-grained and dynamic scene analysis remains unclear. Here, we combined over-ground walking with mobile EEG and a transitional click-train paradigm to test how natural locomotion influences auditory processing in humans. Participants listened to two-segment click trains in which a subtle inter-click-interval (ICI) change signaled a pitch shift and performed a task-engaged change-detection task while either sitting or walking; an independent cohort also completed a passive-listening version. Walking elevated behavioral detection thresholds and slowed responses, indicating reduced sensitivity to fine temporal changes. Neurally, locomotion produced a response-component-specific attenuation: activity time-locked to the ICI transition--the change response previously linked to temporally integrative updating of an ongoing auditory object--was strongly reduced, whereas the offset response was largely preserved and onset responses were only modestly affected. Critically, this modulation persisted during passive listening and was selectively amplified near the perceptual threshold during task-engaged detection, revealing an interaction between motor state and cognitive demand. Thus, natural locomotion does not uniformly degrade hearing; instead, it preferentially down-weights a behaviorally critical, temporally demanding stage of auditory processing, offering a framework for understanding how motor-cognitive state shapes auditory scene analysis in the moving brain.