Calibration of SEER signals at high temporal resolution. A stained cell held at 0 mV under voltage clamp was subjected to biphasic pulses of 400 ms illustrated in B, and line scanned as in Fig. 8. (A) SEER ratio images R(x,t) for five pulse amplitudes. (B) Line-averaged, normalized ratio, R(t), during the corresponding pulses. (C) R(t), averaged during the last 150 ms of each pulse (a time when the transient had settled) versus the applied voltage. The line plots the best linear fit to all points between −100 mV and +100 mV; its slope is 0.103 (100 mV)⁻¹. ID: 091912a.