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Photoreceptor topography and cone-specific electroretinograms
It is implicit in many cone-specific ERG studies that the amplitude is proportional to the numbers of cones stimulated. The objective of these experiments was to test this idea by comparing ERGs obtained from different areas of the retina with histological data on cone-density distributions. The his...
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Published in: | Visual neuroscience 2004-05, Vol.21 (3), p.231-235 |
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Main Authors: | , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | It is implicit in many cone-specific ERG studies that the amplitude
is proportional to the numbers of cones stimulated. The objective of
these experiments was to test this idea by comparing ERGs obtained from
different areas of the retina with histological data on cone-density
distributions. The histology (Curcio et al.,
1990) shows that the cumulative number of cones in the human
retina increases exponentially with stimulus diameter between 0- and
40-deg eccentricity. L-, M-, and (L+M) cone-driven 30-Hz ERGs were
obtained from a series of stimuli with one of the following
configurations: (1) Circular stimuli of different angular subtense up
to 70-deg diameter. (2) Annuli with 70-deg outer diameter but variable
inner diameter. (3) Annuli of constant area but increasing
eccentricity. Cone contrasts were equalized for each stimulus
condition. The modulated and nonmodulated regions of the screen had the
same mean hue and luminance. The data suggest that the L+M cone ERG
amplitude increases with stimulus diameter in direct proportion to the
estimated number of cones stimulated. Furthermore, the total L+M
responses appear to be predicted from individual L and M responses by
simple linear summation for both the disc and annular stimuli. |
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ISSN: | 0952-5238 1469-8714 |
DOI: | 10.1017/S0952523804213268 |