Robustness of respiratory rhythm generation across dynamic regimes
Fig 12
Effect of increasing drive from PiCo to the post-I unit (a53) on respiratory period.
(A) Period (black) and expiratory phase duration (red) for c11 = −0.03 (pre-I unit intrinsically oscillatory). (B) Period (black) and expiratory phase duration (red) for c11 = 0.01 (pre-I tonic). Note that the entire change in period is captured by the change in expiratory phase duration in both (A) and (B). (C) Trajectories projected into the slow phase plane for the pre-I unit with c11 = −0.03 for a53 = 0 (without PiCo activity, grey) and a53 = 0.4 (with PiCo activity, magenta). The curves of fixed points (green, FP) and left knees (blue, LK) for the pre-I unit dynamics are also shown. (D) Trajectories projected into the slow phase plane for the pre-I unit with c11 = 0.01 for a53 = 0 (grey) and a53 = 0.4 (magenta). FP and LK as in (C). In both (C) and (D), the projected trajectories reach the points marked with circles at the start of the aug-E phase. The arrow indicates the direction of flow.