Figure 7.

Modeled photoreceptor responses at increasing levels of light adaptation. Impulse responses (left) and transfer functions (right) for the components of a simple feedback model of photoreceptor responses at increasing levels of light adaptation. (A) P, the response of the photoreceptor in the absence of feedback, corresponding to the dark-adapted state. (B) The feedback transformation F. (C) The resulting photoreceptor output, L (Eq. 6). The g = 0-curve (solid) is the same as (A); the dashed curves correspond to g = 0.1, 0.2, 0.5, and 1. (D) The photoreceptor responses reported by Schneeweis and Schnapf (2000), as in Figure 6. All curves are shown peak-normalized; transfer functions are plotted as a function of frequency, f = ω/2π.