Appendix 8—figure 7. Refractory sampling enhances neural resolution for different aspects of hyperacute images.

(A) Examples of simulated macroscopic light-induced current responses (normalized LICs) of two different photoreceptor models. Both models have 30,000 microvilli. In the first model (red), every photon causes a quantum bump; hence, its photon sampling has no refractoriness. In the second model (black), photon sampling is refractory. Both models are stimulated with the same moving two bright dots, with their actual light inputs being first modulated by photomechanical rhabdomere contractions (following the microsaccadic sampling hypothesis). Based on the tests with different velocities and inter-dot-distances, refractoriness consistently causes a phase lead in LIC responses. (B) Refractoriness improves response resolution for hyperacute stimuli (inter-dot-distance <4.5^o) at slow velocities (≤20 ^o/s). The resolvability, D, of the recordings and simulations, was determined by Raleigh criterion (cf. Figure 7C). (C) An example of how refractoriness can enhance response resolution for larger stimulus separations at high saccadic velocities. The difference from the lower peak to the trough is larger in the black trace (refractory photon sampling) than in the red trace (complete photon sampling).