Figure 6. Dynamical states of the network during a current injection (I _MF = 22.7 pA) with various concentrations of Mg²⁺.

A, Dependence of the oscillation index (OI) and POT representation index (PI) on the concentration of Mg²⁺. OI was large in two separate regions of Mg²⁺ concentration, which are indicated by the vertical gray bands. In-between these gray bands, there is a domain in which PI was larger than 0.5. B, Average firing rate of grcs and frequency of oscillatory spike generation. The average firing rate increased monotonically as the Mg²⁺ concentration increased. The oscillation frequency was around 7 Hz within the interval of 0.417–0.782 µM and around 20 Hz within the interval of 5.21–9.13 µM.