Appendix 6—figure 3. Photoreceptor response maxima lag moving objects.

(A) Channel 1 input was driven by an incremental ramp to create an image of a bright dot (point-object) moving from the No.1 light-point to the No.25 (front-to-back). Similar decremental ramps were used to produce back-to-front motion. (B) Intracellular responses of Calliphora photoreceptors to a moving point-object showed two response peaks: a large peak at t₂, which corresponded to the moment it travelled pass the cell’s optical axis at t₁, and a smaller peak at t₄ caused by the exceptional brightness of light-point No.22, which was turn on at t₃. x was the object’s travelling time. (C) An example of the linear correlation between t₂ and x. Below each data point is its corresponding stimulus (dot) velocity. (D) An example of the linear correlation between t₄ and x. Again, the corresponding dot velocities are shown.