Comparison of the focal electroretinogram and the pattern electroretinogram in the pigeon

A comparison has been made, under focal conditions, of the electroretinogram (e.r.g.) and the pattern electroretinogram (p.e.r.g.) of the central yellow field of the pigeon retina, using vitreal and intraretinal recordings. The sum of the on and off e.r.g. is of shorter time-to-peak and of smaller amplitude than the p.e.r.g. elicited by a grating of 1 cycle/degree, as predicted by the spatial tuning of the p.e.r.g. Depth profiles were made to compare with p.e.r.g. and the sum of the on and off e.r.g. The two responses co-vary in terms of amplitude, time-to-peak and form. This suggests that the p.e.r.g. has a conventional electroretinographic location.