Fig. 5

Fluorescence changes in GECI-expressing neurons in dissociated culture in response to intracellularly induced APs a Fluorescence changes in iYTnC2- and GCaMP6s- expressing cells to the train of 10 APs intracellularly induced with a frequency of 50 Hz. Ca²⁺ responses were averaged across representative recorded neurons in different wells (N = 6 for GCaMP6s and N = 10 for iYTnC2). Example of intracellular recording (grey) was taken from one representative cell. b Dependence of the amplitudes of responses induced by different numbers of APs in neurons expressing iYTnC2 and GCaMP6s. The linear regression was calculated for the 2–50 APs subset for both iYTnC2 and GCaMP6s. In the range of 2 to 50 APs the dependence is linear for both indicators while the amplitude of response to 100 APs in GCaMP6s-expressing neurons lies well below the linear regression line. At the same time response of iYTnC2 to 100APs is located directly on 2–50 regression line, i.e. dependence remains linear even for responses to strong stimulation. Values are shown as the means ± SEM