HC-cone feedback increases the efficiency of color induction at the optic nerve.

<p>(A,B) Spectral sensitivity of the optic nerve measured from saline-treated retina (S) and retina treated with saline and cobalt (S + Co). Application of cobalt induced a change in the shape of spectral sensitivity, increasing the sensitivity to long wavelengths (observed for sensitivity measured under both backgrounds). Error bars, ±1 SEM. Sample size: S: Natural = 5, LW adaptation = 5; S + Co: Natural = 5, LW adaptation = 5. (C) The efficiency of color induction, as indicated by the RMSE between the spectral sensitivity under the two backgrounds, decreased significantly with the application of cobalt (marked with an asterisk; see text for statistics). Box specifications as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0066216#pone-0066216-g003" target="_blank">Figure 3</a>.