Figure 2.

A) Time series of external torque stimulus and sensor noise across 6 repeated cycles. Noise was added as pink noise that was further low pass filtered to mimic spontaneous sway RMS and power spectra in previous studies. B) Power spectra of noise and torque stimulus (T_ext =3 N^.m peak amplitude). C) Illustration of realistic simulated lower body (θ₁) and upper body (θ₂) sway evoked by T_ext when the simulation included sensory noise. Because there were small systematic errors in sway responses obtained from T_ext simulations (sway angle errors shown in D) an alternative method was used to add noise to the frequency response functions (see Methods).