(a) Correlation plot of the fluorescent signal changes against the swimming speed in the anterior hindbrain (ant. hind), posterior hindbrain (post. hind), the medial midbrain (med. mid), and the optic tectum (OT) from the ROIs shown in Figure 1c. As compared to the other brain regions, OT showed lower correlations with speed. The plots in the right column show the same analysis for an animal with panneuronal expression of GFP instead of GCaMP6s (tg(HuC:Gal4;UAS:GFP x Ath5:Gal4) in which no correlated regions (more than 4 connected voxels) were found at the same threshold (p<10-5). b) Cluster analysis complementing the regression analysis shown in Figure 1c also identified highly correlated signal changes in the the anterior and posterior hindbrain regions (e.g., yellow cluster when searching for maximally 8 clusters). (c) Correlation plots vs. swimming speed of the fluorescent signal detected in the left and right cerebellum (ce) (and both sides combined) from a fish with selective expression of GCaMP6s in only the granule cells of the cerebellum (tg(gSA2AzGFF152B;UAS:GCaMP6s) corresponding to the experiment shown in Figure 1d.