Refined calibration methods for optical potential mapping in single cardiomyocytes

Fluorescence imaging provides a comprehensive view of the electrical behavior of excitable cells, the relative nature of the optical signals however requires additional means for calibration. The determination of the actual electrical field strength is subject to uncertainty even when using concurrent electrode measurements. A combined approach of electrical field measurement and optical mapping of the spatially distributed polarizations provides a satisfying calibration of the optical signals in our field-stimulation experiments.