ERGs of <i>rd1</i>_Opto-mGluR6 mice show an inverse, electronegative b-wave.

<p>(A) Negative deflection in response to a strobe flash measured in <i>rd1</i>_Opto-mGluR mice. (B) Blind <i>rd1</i> littermates had no detectable ERG. (C,D) The ERGs of seeing <i>Pde6b</i>⁺ mice to a low-intensity (C) and high-intensity (D) strobe flash. ERGs of nonsaturating light intensities (C) lack oscillatory potentials and show slowed b-wave kinetics compared to ERGs of saturating light intensities (D). (E,F) Pharmacology on the electronegative ERG depicted in (A), before (grey traces) and after (broken traces) intravitreal injection of inhibitors. Application of DL-APV and L-AP4 slowed the response kinetics (E), and additional application of CNQX increased the ERG amplitude (F). The black trace in (E) shows the ERG of the control (left) eye after the inhibitor mix has been injected into the contralateral (right) eye; no change in the ERG is visible in this internal control.