“…Similar to master and slave synchronization of neural networks and chaotic systems [4], [5], [6], synchronization of two coupled HR neurons (master and slave neurons) has attracted increasing attention [7], [8], [9]. Several papers consider how to design the external control in one neuron, including linear feedback control, adaptive control, or other nonlinear control to achieve the synchronization of two coupled HR neurons [10], [11], [12], [13], [14], [15]. However, external control in one neuron may be very difficult even impossible to be realized [16] from the theory of neuroscience and molecular biology.…”