Noise and delay sustained chimera state in small world neuronal network

Chimera state in neuronal network means the coexistence of synchronized and desynchronized firing patterns. It attracts much attention recently due to its possible relevance to the phenomenon of unihemispheric sleep in mammals. In this paper, we search for chimera state in a noisy small-world neuronal network, in which the neurons are delayed coupled. We found both transient and permanent chimera state when time delay is close to a critical value. The chimera state occurs due to the competition between the synchronized and desynchronized patterns in the neuronal network. On the other hand, intermediate intensity of noise facilitates the occurrence of delay-sustained chimera states. Comparison between noise and delay shows that time delay is the key factor determining the chimera state, whereas noise is a subordinate one.