I. Introduction
For the past few years, coupled neural networks (NNs) have been extensively studied in diverse fields, such as brain neuroscience, biology, and chemistry [1], [2]. Synchronization is an interesting and significant dynamic behavior of coupled NNs, which has been investigated in depth, and a large number of crucial theoretical results have been acquired [3]–[8]. Coupled NNs can realize many dynamic characteristics through electronic circuits, but when electrons move in asymmetric electromagnetic fields [9]–[11], the diffusion effect is inevitable and the coupled reaction–diffusion neural network (RDNN) model is obtained. As research shows, the human brain has the ability to process information in parallel, which is similar to the synchronization of coupled RDNNs. In order to better simulate the function of the human brain and promote the progress of brain neuroscience, it is necessary to research the synchronization problem of coupled RDNNs and many important theoretical achievements have been gained in [12]–[16].