Spatial properties of the oscillatory potentials of the frog electroretinogram in relation to state of adaptation.

The spatial characteristics of the oscillatory potentials (OPs) and the a- and b-waves of the frog electroretinogram (ERG) were studied during different states of adaptation induced by repetitive light stimulus given at 1 min or 15 sec interval. The spatial integration area of the OPs was found to be reduced during relatively more light-adapted conditions compared to relatively more dark-adapted ones. No major adaptive effect on the spatial summation area of the a- and b-waves observed. The results indicate that the spatial changes of the OPs observed may be signalled by the amacrine cells which would thus be indirectly involved in the generation of the OPs. The spatial properties of the OPs differed from that of the a- and b-waves suggesting that the OPs have a different origin to that of the a- and b-waves. Finally, the present data indicate a clear and sensitive spatial organization in the frog ERG.