Figure 6.
Simulation of Poisson light absorption model for different light intensity time series. RandPAM can be used to simulate photon arrival process of a fly photoreceptor to any light intensity time series with different statistical properties. Here, we test it with two light sequences, a 20 Hz band-limited Gaussian white noise (WN) and a naturalistic stimulus (NS), whose power spectra follows 1/f statistics (f: temporal frequency). The light intensity is given as photons/ms. RandPAM takes the photons in the stimuli and distributes them into a given number of microvilli (sampling units). The photon-hits of all microvilli must add up to the original input, as the model's underlying assumption is that all the photons become absorbed. The model produces identical light patterns as the input (A,B). (A) Simulation of WN pattern at BG_1 (light level of 105 photons/s); (B) Simulation of NS pattern at BG_1 (light level of 105 photons/s). In each sub-figure, the dotted line (blue) is the light input and the solid line (red) is the simulation result. Because these curves overlap perfectly, the blue curves are right-shifted by 1 ms.