Structured visual and somatosensory stimuli evoke modality-invariant positional and modality specific velocity dynamics during standing

Abstract Standing postural control is adaptable to environmental constraints. Center of pressure velocity during support surface translations shows the postural control system utilizes feedforward and feedback control mechanisms to adapt to different environmental structures. It is not clear whether the postural response to structured support surface stimuli is modality specific. This study investigated postural responses to support surface translations and visual surround rotations structured to mimic white, pink, or red noise. Positional entrainment was analyzed using cross correlation and cross sample entropy, and velocity responses were analyzed using mean velocity and detrended fluctuation analysis. Entrainment was strongest for red noise and weakest for white noise. Pink noise was similar to white noise for the support surface translations and red noise for the visual surround rotations. Short-term persistence of the postural response was weakened for support surface translations and strengthened for visual surround rotations, it was also affected by the persistence of the stimulus, with stronger response persistence associated with stronger temporal correlation. Long-term anti-persistence became stronger only in the support surface translations and average velocity increased in both modalities. These data indicate differential effects due to the modality of stimulus, but similar effects due to the structure of the stimulus.