Figure 1. Experimental design.

Baseline (green) and experimental (red) period stimuli were unchanged across c, nc and v BH tasks. Between condition types only the preparation period was modified to either include feedback (stimuli changed at threshold chest expansion) or no feedback (remained yellow for full 3 seconds regardless of extent chest expansion). The primary task (A) was performed by all subjects. The alternate design (B) was performed on the last subject only.