  We study the critical features of coupling parameter in the synchronization
of neural networks with diluted synapses. Based on simulations, the exponential
decay form is observed in the extreme case of global coupling among subsystems
and fully linking in each network: there exists maximum and minimum of the
critical coupling intensity for synchronization in this spatially extended
system. For the partial coupling, we present the primary result about the
critical coupling fraction for various linking degrees of networks.
