Fig 7. Ca²⁺ oscillation frequency and amplitude for different values of the volume ratio between the internal Ca²⁺ store and the intracellular space (ratio_ER), as well as the maximal pump currents of the Na⁺/Ca²⁺ exchanger (I_NCXmax) and the glutamate transporter (I_GluTmax).

The astrocytic compartment was stimulated for 200 seconds with a Poisson spike train of 100 Hz. a Ca²⁺ oscillation frequency for three different values of ratio_ER (0.08, 0.1 and 0.15), as a function of I_GluTmax and I_NCXmax. The colored lines correspond to I_NCXmax equal to 0.0001$\frac{pA}{\mu m^2}$ (blue), 0.001$\frac{pA}{\mu m^2}$ (yellow), 0.01$\frac{pA}{\mu m^2}$ (gray), 0.1$\frac{pA}{\mu m^2}$ (green) and 1$\frac{pA}{\mu m^2}$ (red). The dashed line corresponds to I_GluTmax equal to 0.68$\frac{pA}{\mu m^2}$. b Ca²⁺ oscillation frequencies for three different values of ratio_ER (0.08 0.1 and 0.15), as a function of I_GluTmax and I_NCXmax. The colored symbols denote the values of I_NCXmax shown in a. c Ca²⁺ oscillation amplitudes for four different values of ratio_ER (0.05, 0.06, 0.1 and 0.15), and as a function of I_GluTmax and I_NCXmax.