Stability of the preparation after repeated exposures during a 20 min interval. a, Representative example of a spiny CA 1 dendritic segment imaged in vivo for five times during a 20 min period (5 min intervals). Each column is a Z series composed of six images (0.7 μm intervals). b, High magnification of the green and red boxed region from a. The image on the left (pseudocolored green) shows spines at time 0, the center image (pseudocolored red) shows the same spines at the fifth imaging session, and the image on the right is a merged image of the green and red images. Scale bar, 1 μm.