Before revision:  The transition from desynchronous spikes to synchronous bursts activities , induced by varying the synaptic coupling, emerges in a hysteretic loop due to a bistable regime where normal (desynchronous) or abnormal ( synchronous) regimes exist.
After revision:  The transition from desynchronous spikes to synchronous bursts activities , induced by varying the synaptic coupling, emerges in a hysteretic loop due to bistability where abnormal (excessively high synchronous) regimes exist.