Figure 3.

Intracellular [Ca²⁺] elevation upon electrode insertion. A. Frames from an optical recording of the jRGECO1a activity are represented. At 0 s, culture had no activity and calcium signal was at baseline. At 15 s, electrode was inserted into the culture. The insertion spot is indicated by a white triangle. After 1 s, elevated calcium signal is localized to the electrode insertion spot. This elevation in calcium signal reaches the maximum coverage around the site of electrode insertion after about 30 s and gradually decreases. By approximately 900 s, the signal is back to baseline. B. Two ΔF/F traces illustrated in green and black colors obtained from the ROIs specified in A. 0 sec frame, are provided respectively. Red bars are corresponding time points of the presented frames in A. C. ΔF/F signals obtained from ROI1 are subtracted from ROI2, aligned by the time of electrode insertion and averaged. Standard deviation is depicted as gray shadow around the black curve.