Enhancement and sustainment of internal stochastic resonance in unidirectional coupled neural system.

In this study, the collective dynamical behavior of two unidirectionally, linearly coupled neurons was investigated. Our investigation illustrates that, depending on the coupling strength, the internal stochastic resonance (ISR) effect observed in one of the two neurons could be amplified or sustained by the other. The amplification of ISR is enhanced as the coupling strength is increased from 0. However, when the coupling strength is increased above a certain level, the amplification of ISR is reduced, implicating that there exists an optimal coupling strength for the information flow between two neurons. As the coupling strength is increased further, i.e., above the critical level, synchronization of the two subsystems is achieved, yet the two subsystems exhibit the same magnitude response to the external noise, suggesting that the information transmission among coupled subunits could not be improved by further enhancing their coupling strength. And similar phenomena could also be obtained for the nonidentical case.