The value at unit x increases and decreases at unit y in the silent phase while the opposite occurs in the active phase. Transitions between phases occur at the two humps of the x-nullcline. Jumps are instantaneous and are denoted by horizontal lines in Figure 2a. Thus oscillations are stimulus-driven. Second, two coupled oscillating units synchronize if they are close enough on the limit cycle.
Synchronization is defined as two or more oscillators that simultaneously jump up and down.
Third, the global inhibitor desynchronizes separate groups using a gating mechanism that allows only one synchronized group into the active phase at a time. When a synchronized group enters the active phase the global inhibitor is excited and in turn sends inhibition to the entire network through S . This causes the x-nullclines of all oscillators to shift down to the case in Figure 2b. Groups in the silent phase are prevented from jumping up. The group in the active phase counteracts the inhibition with local coupling.