Supplementary Figure 6: Characterization of the spatial extent of photostimulation deep inside the larval zebrafish brain

a, Dorsal-view maximum intensity projections and lateral-view slices of anatomy reference stacks acquired before and after photostimulation of targets in the brains of PA-GFP-expressing larval zebrafish. Target E was photoactivated in specimen #3, and targets F and G were photoactivated in specimen #4 (please see SI Supplementary Fig. 5 for targets A-D in specimens #1 and #2). The depths of targets E, F and G relative to the surface of the brain were 180.0 µm, 172.5 µm and 178.0 µm, respectively.b, Dorsal- and lateral-view maximum intensity projections of the photoactivated regions E, F and G.c, Intensity profiles of photoactivated regions along lateral and axial directions and corresponding FWHM size. The spatial extent of activated regions (7-8 µm axially and 5-7 µm laterally) was found to be uniform across the brain and consistent with the resolution characterization based on a florescent dye shown in Fig. 5 (please also see the legend of SI Supplementary Fig. 5c in this context). The experiment shown in this figure was repeated independently once with similar results (for similar depths in the fish brain). Scale bars, 100 µm (a), 5 µm (b).