Tactile suppression during movement as optimal integration of somatosensory feedback across time

When reaching for an object, tactile sensations from a sleeve sliding over the moving arm are often ignored, yet the computational principles governing this phenomenon remain unclear. Prevailing accounts propose that the nervous system reduces tactile sensitivity by prioritizing internal predictions over somatosensory feedback, but a quantitative explanation of its temporal dynamics has been lacking. Here, we show that tactile suppression is a consequence of optimal state estimation during movement. Using optimal feedback control theory, we predicted how the nervous system should dynamically weight uncertain internal predictions against noisy somatosensory input. Human participants performed goal-directed reaching movements while vibrotactile stimuli were delivered at different time points. Suppression weakened when internal uncertainty about hand position increased, consistent with greater reliance on sensory feedback. These results identify tactile suppression as a consequence of continuous and dynamic uncertainty-dependent sensorimotor state estimation rather than fixed gating, revealing a normative principle governing tactile sensitivity during action.