Receptors as a master key for synchronization of rhythms.

A simple, but general, scheme to achieve synchronization of rhythms is proposed. It can handle both external synchronization and self-synchronization within a single mathematical framework. In this scheme, external linear stimulations can be converted into internal nonlinear stimulations by the mathematical model receptor without breaking the regular motions of limit cycle oscillators. Thus, even a small external periodic stimulation can work very efficiently for achieving synchronization. Stimulation via model receptors is much more effective for synchronization than mechanically forced stimulations, and the phenomenon called N:M phase locking (N not equal to 1, M not equal to 1) can be suppressed in the weak coupling domain, too.