Figure 3.

Effect of electrical field stimulation of alternating polarity in fibers with phasic and delayed AP-induced Ca²⁺ transients. (a) Left, line-scan images of phasic AP-induced Ca²⁺ transients elicited by field stimulation of alternate polarity and measured in two different regions of interest (ROIs); right, time course of the phasic AP-induced Ca²⁺ transients measured at two ROIs (ROI 1 and ROI 2) and elicited by the stimulus of positive (upper traces) or negative polarity (lower traces) at the fiber end where the recordings were made. (b) Left, line-scan images of phasic-delayed AP-induced Ca²⁺ transients elicited by field stimulation of alternate polarity and monitored in two ROIs; right, time course of the delayed AP-induced Ca²⁺ transients measured at two ROIs and elicited by the stimulus of positive (upper traces) or negative polarity (lower traces) at the fiber end where the recordings were made. The red mark in line-scan images indicates the time when the field stimulus was applied; the dashed rectangles illustrates the location of the ROIs.