  We study the effect of spatially correlated noise on coherence resonance (CR)
in a Watts-Strogatz small-world network of Fitz Hugh-Nagumo neurons, where the
noise correlation decays exponentially with distance between neurons. It is
found that CR is considerably improved just by a small fraction of long-range
connections for an intermediate coupling strength. For other coupling
strengths, an abrupt change in CR occurs following the drastic fracture of the
clustered structures in the network. Our study shows that spatially correlated
noise plays a significant role in the phenomenon of CR through enforcing the
clustering of the network.
