Selective Ca2+ uncaging in the two astrocytes in the center of the field by two-photon photolysis of the acetoxymethyl ester Ca2+ cage DMNP-EDTA which triggers a Ca2+ wave that propagated through the astrocyte syncytium. The Ca2+ indicator Rhod-2 monitors the [Ca2+]i. Red marks indicate 10 ms laser flashes in astrocytes. Acquisition rate = 1.9 sec/frame (86 frames). (Credits: Dr. Brian MacVicar (bmacvica@interchange.ubc.ca) and Sean Mulligan)