Video 4

Movie S4. Photostimulation of the PER with ChR2-T159C. Light from a mercury lamp was passed through a GFP excitation band-pass filter (∼1 s, 0.2 mW/mm2 at 460 nm) to activate ChR2-T159C (driven by Gr5a-GAL4; plus retinal; Left). For comparison, a fly expressing ChR2-wt (plus retinal; Right) shows no response.