Beta wave of the scotopic (rod) electroretinogram as a measure of the activity of human on-bipolar cells.

The beta wave of the human electroretinogram (ERG) is widely believed to reflect the activation of on-bipolar cells. However, the shape of the beta wave is also influenced by the activity of other cell types. To assess how the activity of on-bipolar cells is reflected in the human ERG, rod ERG's were recorded in the dark and on the steady fields. Derived P2 responses were obtained by computer subtraction of the receptor contribution to the ERG. The light-adapted derived P2 was shown to have properties similar to those predicted from previous studies of on-bipolar activity. This was also true of the dark-adapted derived P2 if a small (less than 10%) contribution from a negative potential was taken into consideration. The derived P2, and under certain conditions the beta wave, can be used to study rod on-bipolar activity.