Fig. 1: Coupling between voluntary action and respiratory phase during the Kornhuber task in Experiment 1.
From: Breathing is coupled with voluntary action and the cortical readiness potential
a Distribution of intervals between button presses (pooled across 20 participants) showed the typical response distribution. b Distribution of respiration phases with respect to the timing of voluntary action onset. Empty black circles represent each participant’s mean respiration phase at button press. Participants initiated voluntary actions more frequently during the late phase of expiration. The polar histogram shows the distribution of all the button presses from 20 participants, which was also concentrated in the late phase of expiration. The red dot indicates the grand-averaged respiration phase at button press. c Histogram of the summed statistics (i.e., minimum number of data points that can be observed in half of the circle; Hodges–Ajne test) obtained from surrogate respiration data. The blue vertical line indicates the summed statistics from original respiration data. The computed test statistics using original data was significantly smaller than chance-level statistics obtained from phase shifted surrogate respiration data (permutation p = 0.0009), confirming the timing of button presses in Experiment 1 is coupled with respiratory phase.
