English: Polyrhythmic dynamics of 3-cell CPGs: from to pattern. Bursting trajectory (gray) in the 3D phase space of the model, which is made of the “active” spiking (solenoid-like shaped) and the flat hyperpolarized sections. The gap between the 2D slow nullcline, , and the low knee on the slow quiescent manifold, , determines the amount of inhibition needed by the active pre-synaptic cell above the synaptic threshold, , to either slow or hold the post-synaptic cell(s) at a hyperpolarized level around . The red, green and blue spheres on the bursting trajectory depict the temporal evolution of the the phases of the [not weekly]-coupled cells of the CPG: active cell(s) above inhibits, in anti-phase, the temporarily inactive cells and visa versa. Inhibitory pulse applied to the blue cell changes the relative phases of the bursting cells so that the CPG pacemaker becomes the green cell after the red cell. Below are shown the corresponding voltage waveforms. This motion picture complements Fig. 10.