SPIKE-TRAIN BIFURCATION SCALING IN 2 COUPLED CHAOTIC NEURONS

We investigate the variation of the out-of-phase periodic rhythm produ ced by two chaotic neurons (Hindmarsh-Rose neurons [J. L. Hindmarsh an d R. M. Rose, Proc. R. Sec. London B 221, 87 (1984)]) coupled by elect rical and reciprocally synaptic connections. The exploration of a two- parametric bifurcation diagram, as a function of the strength of the e lectrical and inhibitory coupling, reveals that the periodic rhythms a ssociated to the limit cycles bounded by saddle-node bifurcations, und ergo a strong variation as a function of small changes of electrical c oupling. We found that there is a scaling law for the bifurcations of the limit cycles as a function of the strength of both couplings. From the functional point of view of this mixed typed of coupling, the sma ll variation of electrical coupling provides a high sensitivity for pe riod regulation inside the regime of out-of-phase synchronization.