Relationship between the electroretinogram (ERG) and the proximal negative response (PNR)

Using the bullfrog retina, depth profiles of Burkhardt's PNR and of the ERG are compared under various recording conditions. When the retina is voltage-annulled so that there is no ERG potential outside the retina, the depth profile of the ERG changes to resemble that of the PNR. When there is current annullment so that there is no ERG current outside, the depth profile of the PNR changes to resemble that of the ERG. Our evidence suggests that Burkhardt's PNR can be further analyzed into a PNR proper, which consists of an initial fast negativity followed by a slow negativity, and a local ERG dominated by the b-wave.