Computational simulation with noise and conceptual scheme of a state point behavior after several intensities of perturbation.

<p>(A–C) Schematic drawings of a limit cycle attractor and a perturbation delivered to the system are shown in the left column. An oscillator (yellow) circulates in the phase plane (X, Y) as shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0181223#pone.0181223.g001" target="_blank">Fig 1</a>. A unique point in the center of the trajectory was the assumed as a singular point where all isochrones converge. When perturbations of varying intensity (yellow arrow) were applied to the oscillator, the oscillator deviated from the trajectory by various distances. (A) In the weak intensity case (blue dots), the oscillator moved in the vicinity of the trajectory where the phase difference was small (type 1 phase resetting). (B) In the moderate case (green dots), the oscillator reached close to the singular point. (C) In the strong case (red dots), the oscillator moved to the opposite area of the trajectory, giving the large phase shift (type 0 phase resetting). The middle column shows the phase response φ_<i>j</i> (<i>j</i> = 1, …30) for each perturbation timing CT (crosses) and mean phase Φ (CT) (filled circles). The right column shows the certainty level <i>R</i> (CT). (D) Minimum of <i>R</i> for each <i>ε</i> value.