Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.05.19.104760v1?rss=1 Authors: Mangalam, M., Kelty-Stephen, D. G. Abstract: Quiet standing exhibits strongly intermittent variability reflecting a richly interactive foundation. This intermittency can be understood in various ways. First, variability can be intermittent through the engagement and disengagement of complementary control processes at distinct scales. A second and perhaps a deeper way to understand this intermittency is through the possibility that closed-loop control depends on the cascade-like interactions across many timescales at once. These diverse control processes suggest specific non-Gaussian distributional properties at different timescales. Multiscale probability density (PDF) analysis shows that quiet standing on a stable surface exhibits a crossover between low non-Gaussianity (consistent with exponential distributions) at shorter timescales reflecting open-loop control, increasing towards higher non-Gaussianity and subsequently decreasing (consistent with cascade-driven Levy-like distributions) at longer scales. Destabilizing quiet standing elicits non-Gaussianity that begins high and decreases across timescales (consistent with cascade-driven Levy-like distribution), reflecting closed-loop postural corrections at more of the shorter timescales. Finally, indices of postural sway govern the appearance or disappearance of crossovers, suggesting that tempering of non-Gaussianity across log-timescale in stable-surface condition is mostly a function of endogenous postural control. These results provide new evidence that cascading interactions across longer-timescales supporting postural corrections can even recruit shorter-timescale processes with novel task constraints. Copy rights belong to original authors. Visit the link for more info