Four different mechanisms for switching cell polarity
Fig 4
Trajectories of the model during switches, classified as four different switching classes.
Signal parameters Xmax and τ and the parameter modified are indicated by the corresponding symbols in Fig 3. Vertical dashed lines indicate the period during which the signal is present. A Relaxation oscillator. For a short signal (plus-symbol), the polarity switches during the applied signal as shown by the solid lines. For a longer signal (open triangle), the system switches a second time as shown by the dashed lines. B Prime-release switch. During the signal the polarity is unchanged, but switches after the signal is released. C Reset switch. During the signal, the system relaxes to a symmetric distribution of the polarity marker and establishes a reversed polarity after the signal is removed. D Push switch. The system switches while the signal is applied and does not switch back when the signal is applied longer.