Figure 2.

Real-time display of precision grip force, ankle displacement, and target signals for concurrent force-matching and postural tasks. To reduce the visual load during the experiment, the target signals of both postural and force-matching tasks were displayed in an identical position on the monitor, by separate scale-tuning of the manual force target and postural target. Force-matching performance was assessed with normalized force error (NFE). The event-related potential (ERP) associated with force-matching was registered with scalp electroencephalography. ERP between the executive tone and the onset of the force-impulse profile was denoted as the preparatory period. ERP in this period primarily contained N1 and P2 components. The ankle displacement after conditioning with a low-pass filter is labeled by three critical events (warning signal, executive tone, and force-impulse onset). TF, target force; PGF, peak grip force.