Expression of cyto-GCaMP3 and Lck-GCaMP3 throughout astrocytes. (A and B) Cartoons of differences between cytosolic and membrane-targeted GECIs. (C) Schematic illustrates the protocol for AAV2/5 microinjections into the hippocampus. The right-hand image shows the expression of Lck-GCaMP3 throughout the hippocampus. (D) Expression within the stratum radiatum region for Lck-GCaMP3 and cyto-GCaMP3 (these panels are also shown in Fig. 2 in the bottom row of images in relation to neuron staining). (E) Representative images showing GFAP and GCaMP3 staining for the stratum radiatum region from control mice that received no AAVs and those that received AAV2/5 Lck-GCaMP3. The image is a zoomed-out view.