Mice with disrupted canonical phototransductive pathways retain robust VEP responses under light-adapted conditions

Abstract

The Gnat1−/−, Gnat2−/−, Opn4−/− triple knockout (TKO) mouse line, lacking alpha transducins in rods and cones and melanopsin in ip-RGCs, is generally considered to be blind. Previous studies using electroretinograms have found that these animals retain residual light sensitivity only under dark-adapted conditions. Here, we show cortical responses to light (visual evoked potentials (VEPs)) recorded from TKO mice under light-adapted conditions. VEPs were recorded from C57BL/6J mice (n=6) and TKO mice (n=5) via 50ms flashes over 4 log units of intensity, with maximal illuminance of 44.3 mW/cm∧2 at the surface of the contralateral eye (λcenter = 530nm).