Stability of Cohen-Grossberg neural networks with nonnegative periodic solutions

In this paper, we discuss nonnegative periodic solutions for generalized Cohen-Grossberg neural networks. Without assuming strict positivity and boundedness of the amplification functions, the dynamics of periodic Cohen-Grossberg neural networks are studied. By applying a direct method, sufficient conditions guaranteeing the existence and global asymptotic stability of nonnegative periodic solution are derived. Also the criterion does not depend on the assumption for amplification functions being upper and low bounded or the external inputs.