Figure 4. Comparison of secondary pathway activity in mouse and primate under identical experimental conditions.

(A) Steady-state measurements of the dependence of rod current on mean light level from suction recordings in primate and mouse as in Figure 2A. Traces are normalized to the peak amplitude of a brief saturating flash. (B) NBQX-insensitive responses to fixed contrast flashes across backgrounds in AII amacrine cells recorded in current-clamp (as in Figure 3). Asymptotic responses in these experiments (and in C-D) represent Weber behavior, not signal saturation. Black and gray arrows indicate primate and mouse 90% rod saturation levels. (C) Horizontal cell current-clamp recordings to short wavelength flashes across a range of rod adapting backgrounds in primate (top) and mouse (bottom) as in Figure 3. (D) Population data from horizontal cell recordings in primate and mouse, normalized to the responses recorded at 2000 R*/rod/s.