Figure 6. Pseudo-balance.

Time-varying changes in coherence between the vestibular stimulus and soleus EMG activity during 100 transitions from human- to computer-controlled motion of the robotic platform. Data are shown for a single subject (A) and the group mean (B) for all five subjects. The 4 s period prior to time zero shows frequency-specific coherence as subjects were braced on top of the platform and balanced its body-like load with their feet. Time zero represents the transition point from human-controlled balancing of the platform to a computer-controlled rotation of the platform along a predetermined path, which lasted for 4 s (between the vertical lines), before subjects regained control of the platform. The mean of the coherence from 0 to 25 Hz at each time point is shown across the bottom panel. Non-significant data points have been removed so that zero coherence represents the values below the threshold of the 99% confidence limit; 0.046 for the single subject and 0.0093 for the group mean data.