Three-dimensional projection of merged image stacks of glial fibrillary acidic protein-green fluorescent protein (GFAP/EGFP) (which visualizes astrocytes) and the fluorescence of the long wavelength Ca2+ indicator Rhod-2-AM (which visualizes an arteriole) displays the selective loading of astrocytes and their endfeet. Neurons and vascular elements did not load with these indicators. (Credits: Dr. Brian MacVicar (bmacvica@interchange.ubc.ca) and Sean Mulligan)