Figure 7—figure supplement 3.

Figure 7—figure supplement 3.

(A) Schematics of opsin expression pattern and behavioural assay. (B) Opsin expression in spinal motor neurons in a Tg(mnx1:GAL4;UAS:GtACR1-tdTomato) larva at 5 dpf. Imaging field of view corresponds to black box in (A). A, anterior; D, dorsal; P, posterior; V, ventral. Scale bar 50 μm. (C) Background-subtracted camera field of view showing Tg(mnx1:GAL4;UAS:GtACR1-tdTomato) larvae positioned in individual agarose wells (left) and tracking of swimming speed for selected larvae (right). Behaviour was monitored at 50 fps across multiple freely-swimming larvae (6 dpf; N = 24 ± 6 fish per group, mean ± SD) while they were subjected to 10 s light periods (459 or 617 nm, 0–2.55 mW/mm²) with a 50 s inter-stimulus interval. (D) Optogenetically-induced changes in bout rate (mean + SEM, across fish) in Tg(mnx1:GAL4) larvae expressing GtACR1 (N = 29 larvae, left) or eArch3.0 (N = 23 larvae, right). Horizontal grey bars indicate the time windows used for comparative quantification of behavioural changes. Each time bin corresponds to 2 s. (E,F) Normalised bout speed during the `LED On` period in larvae expressing different opsins (mean ± SEM, across fish). Control opsin-negative siblings were subjected to the same light stimuli.