Figure 1. Dark-adapted ERG of Gnat1^−/− mice. A shows representative dark-adapted ERG traces from Gnat1^−/− mice recorded in response to white flashes of increasing irradiance at subjective midday (CT6) after approximately 18 h dark adaptation. B and C show quantification of b-wave amplitude and implicit time of ERGs from Gnat1^−/− (black) and wild-type (gray) mice. Implicit time could only be measured when a reliable b-wave was discerned and is therefore absent at lower flash intensities. The arrow in A indicates flash onset and numbers on left indicate irradiance in log W/m² (these radiometric irradiances equate to ~–1.0 to 2.5 log cd-sec/m²). Data in B and C is shown as mean±SEM. Replicates for B and C are: n=6 for Gnat1^−/−; n=8 wild-type.