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. Author manuscript; available in PMC: 2010 Jan 25.
Published in final edited form as: J Vis. 2009 Feb 12;9(2):15.1–1518. doi: 10.1167/9.2.15

Figure 8.

Figure 8

1F and 2F responses of a MC cells as a function of modulation direction in an M,L color space at different temporal frequencies. (A) Sketch of cone modulation for luminance modulation, chromatic modulation, and the silent substitution conditions. (B) Response of an MC on-center cell to different conditions (9.8 Hz; mean RMS contrast for M, L cones 30%). For the response to luminance modulation the 1st harmonic dominates. For the other conditions, there is a marked 2F component, even for the silent substitution conditions. This indicates that the 2F component is not due to a simple non-linearity of cone summation. (C–E) 1F and 2F response components as a function of modulation direction in L,M cone space at three frequencies as indicated. Mean cone contrast was held constant for each condition. The 1F response is maximum to luminance modulation and minimum to chromatic modulation. At 2.4 and 9.8 Hz, the 2F response is minimum to luminance modulation, marked to the silent substitution conditions and maximum to chromatic modulation.