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The visual evoked potential as a function of contrast of a grating pattern
Author(s) -
Campbell F. W.,
Kulikowski J. J.
Publication year - 1972
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.1972.sp009801
Subject(s) - contrast (vision) , grating , neuroscience , function (biology) , visual evoked potentials , optics , physics , psychology , biology , microbiology and biotechnology
1. It was shown that the potentials evoked by using a grating pattern alternated in phase at 8 Hz is proportional to the logarithm of the supra‐threshold contrast. Other functions were considered, but they did not describe the data so parsimoniously. 2. The same logarithmic function described the results when a grating was simply flashed on and off; therefore, the apparent movement accompanying the phase alternations is not necessary to evoke the potential. 3. The contrast at which the evoked potential reached the theoretically zero voltage ( C 0 ) was compared with the psychophysical contrast threshold, determined by means of proportion‐of‐time seen measurements; the C 0 contrast corresponded to 50% time seen. 4. The potential, corrected for the proportion‐of‐time seen, was found linearly related to contrast.