The postnatal development of the oscillatory potentials of the electroretinogram. II. Photopic characteristics.

The postnatal development of the oscillatory potentials (OPs) of the rat's electroretinogram (ERG) was studied during more extreme photopic conditions. The appearance of the OPs was further delayed, by 1 to 3 days, compared to previously studied less photopic conditions. A rapid phase of development of the total OP activity occurred at the age of 15 days, which coincided with the physiological opening of the eye-lids. During maturation the first two OPs were enhanced while the later OPs were attenuated. The total OP activity culminated at the age of 30 days. These results strongly indicate that the rapid neuronal adaptive system appears and develops later than the slow photochemical one. Secondly, the fast phase of maturation of the neuronal adaptive process, as reflected in the OPs, seems to be dependent on environmental light. Thirdly, the findings support previous indications that two different systems seem to be responsible for the OPs in the rat and thus the earlier OPs to have different origins from those of the later ones.