  We have studied the synchronization in finite $N$-unit FitzHugh-Nagumo neuron
ensembles subjected to additive and multiplicative noises, by using the
augmented moment method (AMM) which is reformulated with the use of the
Fokker-Planck equation. It has been shown that for diffusive couplings, the
synchronization may be enhanced by multiplicative noises while additive noises
are detrimental to the synchronization. In contrast, for sigmoid coupling, both
additive and multiplicative noises deteriorate the synchronization. The
synchronization depends not only on the type of noises but also on the kind of
couplings.
