Phase-Dependent Transient Responses of Respiratory Motor Activities following Perturbation of the Cycle
Dynamics of an oscillator can be characterized by its behavior following a brief perturbing stimulus. The transient behavior of the oscillator returning to its steady state provides insights regarding the intrinsic properties of the oscillator. In Figure 1, the phrenic nerve activity represents the respiratory oscillation. The timing of the oscillator may be altered following the perturbing stimulus relative to that predicted from unperturbed breaths. This shift in timing is referred to as phase-resetting. We define old phase as the time from the onset of phrenic activity to the onset of the stimulus, and phase shift as the amount of resetting. The relationship between old phase and phase shift characterizes the respiratory oscillator, and called as a phase response curve. Description of phase-resetting characteristics have focused on only one phase of the respiratory oscillator, i. e., the onset or the offset of phrenic nerve activity (e. g. Paydarfar et al. 2 ). We monitored expiratory as well as inspiratory activities to examine the transient behavior of this oscillator in every phase.
KeywordsSimulated Response Respiratory Rhythm Phase Response Curve Superior Laryngeal Nerve Phrenic Nerve Activity
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