  Here we present a study of stochastic resonance in an extended
FitzHugh-Nagumo system with a field dependent activator diffusion. We show that
the system response (here measured through the output signal-to-noise ratio) is
enhanced due to the particular form of the non-homogeneous coupling. Such a
result supports previous ones obtained in a simpler scalar reaction-diffusion
system and shows that such an enhancement, induced by the field dependent
diffusion -or selective coupling-, is a robust phenomenon.
