Identification of de- and hyperpolarized membrane regions in a neuron placed in the electric field (arrow). Top image (gray) is the neuron stained with FluoVolt dye. At the bottom, the same image (in green) is combined with images of the emission gain (red) and loss (blue) by the end of a 2-μs, 257 V/cm square pulse. Two regions of interest (ROIs 1 and 2) were placed over the most hyper- and depolarized areas, respectively; for clarity, they are shown in the gray image with blue and red contours. Arrow is the electric field direction. Scale bar: 20 μm.
