Dynamics of a hybrid system of a brain neural network and an artificial nonlinear oscillator

In the brain, many functional modules interact with each other to execute c omplex information processing. Understanding the nature of these interactio ns is necessary for understanding how the brain functions. In this study, t o mimic interacting modules in the brain, we constructed a hybrid system mu tually coupling a hippocampal CA3 network as an actual brain module and a r adial isochron clock (RIC) simulated by a personal computer as an artificia l module. Return map analysis of the CA3-RIC system's dynamics showed the m utual entrainment and complex dynamics dependent on the coupling modes. The phase response curve of CA3 was modeled regarding the CA3 as a nonlinear o scillator. Using the phase response curves of CA3 and RIG, we reconstructed return maps of the hybrid system's dynamics. Although the reconstructed re turn maps almost agreed with the experimental data, there were deviations d ependent on the coupling mode. In particular, we noted that the deviation w as smaller under the bidirectional coupling conditions than during the one- way coupling from RIC to CA3. These results suggest that brain modules may flexibly change their dynamical properties through interaction with other m odules. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.