Abstract

In the human ERG, the leading edge of the rod a-wave reflects the mass response of the rod photoreceptors.¹ It can be fit with a computational model of the activation phase of transduction to provide parameters analogous to those obtained from individual photoreceptors in vitro.^2-4 However, the photoreceptor response extends for at least several hundred milliseconds following a flash⁵ and is obscured over much of its extent by post-receptoral ERG components. It is only when the test flash is extremely intense (above approx. 4.0 log sc td-s) that the a-wave reaches its maximal saturated amplitude prior to the onset of the b-wave. We have shown previously that it is possible to use a two-flash paradigm to probe the recovery phase of the photoreceptor response.⁶ Our previous work focused on recovery from intense flashes under dark-adapted conditions, where recovery may be limited by the lifetime of activated rhodopsin. The present study extends this analysis to dimmer test flashes and determines the effects of light adaptation on the inactivation phase of the rod photoresponse.

© 1996 Optical Society of America