Appendix 6—figure 6. Resolving two moving point-objects.

(A) Two light-points (bright dots) moving together were presented in the tested photoreceptor’s receptive field at 19°C. The dots were 6.8° apart and travelled at 409°/s in the front-to-back direction. For clarity, neutral density filters and the LEDs pads used for background illumination are not shown in this picture. (B) In Dim, 12 out of 18 wild-type photoreceptors could resolve them, showing the response waveform depicted by the continuous line, with the larger trailing peak. While six other could not distinguish the two objects; showing the waveform of by the dotted line. In Bright, 5 out of 6 examined wild-type photoreceptors resolved the two dots. (C) Response waveform of hdc^JK910 R1-R6s exhibited two distinct peaks, with the leading one was the larger. In Dim, 15 out of 16 tested mutant photoreceptors could resolve the two objects and 14 of them displayed this waveform. In Bright, all of 8 recorded hdc^JK910 photoreceptor responses resolved the objects. D-values were calculated from the amplitude of the smaller peak and the dip in between. (D) In Dim, D-values of hdc^JK910 R1-R6 responses were significantly larger than their wild-type counterpart. D_wild-type = 4.51 ± 0.67%, D_hdc = 10.5 ± 1.35%, p = 0.00075, t-test, n_wild-type = 12, n_hdc = 15. (E) In Bright, the difference of D-values of the two photoreceptor groups was statistical insignificant. D_wild-type = 9.81 ± 1.65%, D_hdc = 16.71 ± 1.86%, p = 0.117, t-test, n_wild-type = 5, n_hdc = 8. (F). ) Changing from Dim to Bright condition, D-values of wild-type photoreceptors appeared to exhibit larger changes than those of mutant photoreceptors. However, the difference was not statistically significant due to the large cell-to-cell variation. R_{C wild-type} = 262 ± 126%, R_{C hdc} = 31 ± 11%, p = 0.164, n_wild-type = 4, n_hdc = 7. (D–F) Mean ± SEM, two-tailed student test.