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You are here: McMaster Institute for Music and the Mind > Publications > Stochastic two-delay differential model of delayed visual feedback effects on postural dynamics

Jason Boulet, Ramesh Balasubramaniam, Andreas Daffertshofer, and Andre Longtin (2010)

Stochastic two-delay differential model of delayed visual feedback effects on postural dynamics

Philosophical Transactions of the Royal Society A, 368:423-438.

We report on experiments and modelling involving the ‘visuo-postural control loop’ in the upright stance. We experimentally manipulated an artificial delay to the visual feedback during standing, presented at delays ranging from 0 to 1 s in increments of 250 ms. Using stochastic delay differential equations, we explicitly modelled the centre-of-pressure (COP) and centre-of-mass (COM) dynamics with two independent delay terms for vision and proprioception. A novel ‘drifting fixed point’ hypothesis was used to describe the fluctuations of the COM with the COP being modelled as a faster, corrective process of the COM. The model was in good agreement with the data in terms of probability density functions, power spectral densities, short- and long-term correlations (Hurst exponents) as well the critical time between the two ranges.

stochastic model, continuous control, postural sway, negative feedback