  Previous works have shown numerically that the response of a ``stochastic
resonator'' is enhanced as a consequence of spatial coupling. Also, similar
results have been obtained in a reaction-diffusion model by studying the
phenomenon of stochastic resonance (SR) in spatially extended systems using
"nonequilibrium potential" (NEP) techniques. The knowledge of the NEP for such
systems allows us to determine the probability for the decay of the metastable
extended states, and approximate expressions for the correlation function and
the signal-to-noise ratio (SNR). Here, exploiting known forms of the NEP, we
have investigated the role of NEP's symmetry on SR, the enhancement of the SNR
due to a "selectivity" of the coupling or diffusion parameter, and discussed
competition between local and nonlocal (excitatory) coupling.
