Temporal modulation of tactile perception during balance control.

Somatosensory feedback, like touch, is essential for body control and movement. Yet tactile sensations from a body part that is about to move or is moving are often suppressed. Most studies on tactile suppression focus on upper-limb movements, where suppression is typically reduced when tactile signals become important to the task. However, how tactile sensitivity changes at other body parts involved in more complex, whole-body actions is widely unexplored. This study examines the temporal tuning of tactile processing on the lower limb during balance control while varying feedback processing demands. Participants stood in a virtual room, with the front wall moving toward them at a moment of high or low temporal uncertainty challenging their posture. Tactile sensitivity was probed using vibrotactile stimuli at the lower leg at different time points relative to perturbation onset. We found that tactile sensitivity while standing improved around the time of perturbation, irrespective of the temporal uncertainty about perturbation onset. Such dynamic modulation indicates a continuous process of sensory feedback regulation to accomplish the task at hand. This expands previous knowledge about sensory integration on the lower limbs during postural control.