Abstract
Purpose:
Prior research has demonstrated band-pass temporal tuning for cVEP. However, it has been argued that this band-pass temporal tuning may result from luminance intrusion due to the effects of retinal homogeneity (e.g., macular pigment distribution) and the use of large stimuli. We tested the claim that such luminance artifacts can explain band-pass temporal tuning of the cVEP using novel stimuli composed of Gabor patches.
Methods:
Participants viewed chromatic patterns modulated along S and LM opponent axes. Patterns comprised 59 reversing Gabor patches increasing in size with eccentricity. Isoluminance was determined individually for each Gabor patch with flicker-photometry. In addition, full-field 2 CPD gratings were presented at nominal isoluminance for comparison with previous published results.
Results:
The psychophysical measurements of isoluminance showed the expected distribution and variability of macular pigment across subjects. The temporal tuning data revealed band-pass characteristics over all conditions including those that account for macular pigment density in the periphery.
Conclusions:
Luminance intrusion due to macular pigment variation across retina does not account for the observed band-pass temporal tuning of the cVEP. As posited previously, the band-pass tuning is likely due to interaction with intrinsic cortical rhythms (e.g., alpha).
Keywords: 471 color vision •
587 macular pigment •
508 electrophysiology: non-clinical