The kinetics and concentration of GECIs strongly influence calcium dynamics.

(A) Quantitative comparisons of the spontaneous calcium signals measured with “GCaMP6s” or “GCaMP6f” as fluorescent reporters. The compared quantities are peak amplitude in terms of ΔF/F ratio (A1), frequency (measured in min⁻¹ for each μm² area, A2) and duration (expressed as full width at half maximum, FWHM) (A3). (B) The impact of the concentration of GCaMP6s in the system on basal concentration of GCaMP-Ca (B1), on the GCaMP-Ca peak amplitude (B2), frequency (B3) and duration (B4) are shown for different values of [GCaMP6s]. Significance is assigned by * for p ≤ 0.05, ** for p ≤ 0.01, *** for p ≤ 0.001. Data are presented as mean ± standard deviation over 20 simulations. Lines are guide for the eyes.