Different rates of growth of monkey and human photopic a-, b-, and d-waves suggest two sites of ERG light adaptation

K. Murayama, P. A. Sieving

Research output: Contribution to journalArticlepeer-review

28 Scopus citations

Abstract

1. We used 200 ms flashes to record the cone driven, photopic ERG of four human subjects and two Macaca monkeys during light adaptation. The 200 ms flashes allowed for separation of the a-and b-waves at light onset from the d-wave at light cessation. All previous similar studies of human and monkey ERG had used only very brief flashes which cause ON- and OFF-components to overlap. 2. The three photopic ERG components all grew during light adaptation, but at different rates. For human, the exponential time constant for growth of the b-wave was significantly smaller than for the a-wave or d-wave (i.e. the b-wave grew fastest). For monkey also, the b-wave grew significantly faster than either the a- or d-wave. 3. Under the model that the a-wave represents cone photoreceptor events and the b-wave represents post-synaptic events, these results suggest that at least two sites of adaptation affect the photopic ERG. 4. We also evaluated the human oscillatory potentials (OPs) and found that both the ON-OPs and OFF-OPs grew during light adaptation. The OFF-OP amplitudes grew proportionally more than did the ON-OPs.

Original languageEnglish (US)
Pages (from-to)385-392
Number of pages8
JournalClinical Vision Sciences
Volume7
Issue number5
StatePublished - 1992
Externally publishedYes

ASJC Scopus subject areas

  • Ophthalmology

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