The oscillatory potentials in response to stimuli of photopic intensities delivered in dark-adaptation: an explanation for the conditioning flash effect.
Previous studies reported that the oscillatory potentials (OPs) evoked to the first flash of a series were always smaller than those produced by the later flashes. This conditioning flash effect (CFE) was suggested to arise from rod inhibition of cone-mediated OPs. We investigated this CFE with the use of two stimulus intensities: 10 cd sec m-2 and 1 cd sec m-2. While the highest intensity did yield the previously reported CFE, the dimmest intensity did not. Our results further indicated that with the brightest stimulus, there is a significant increase in the interpeak interval of the OPs, while dimmest stimuli failed to reveal a similar marked increase. We also noted a significant correlation between the frequency domain of the OPs (as estimated with the interpeak interval) and the amplitude of the OPs (individual or collective: SOPs). Our results would also suggest that the observed CFE could result from a cone inhibition of rod-mediated OPs.
Lachapelle
P
P
Department of Ophthalmology, McGill University-Montreal Children's Hospital, Quebec, Canada.
Benoit
J
J
Blain
L
L
Guité
P
P
Roy
M S
MS
D000221:Adaptation, Ocular / Q000502:physiology; D000293:Adolescent; D000328:Adult; D003623:Dark Adaptation / Q000502:physiology*; D005074:Evoked Potentials, Visual / Q000502:physiology*; D006801:Humans; D010775:Photic Stimulation; D010783:Photometry; D010786:Photoreceptor Cells / Q000502:physiology; D013997:Time Factors