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. 2011 Nov 16;31(46):16833–16843. doi: 10.1523/JNEUROSCI.2505-11.2011

Figure 4.

Figure 4.

A unique S-cone contribution to the PON response. A, Mean responses of sustained cells in Opn4−/− or rd/rd cl (black lines) and Opn1mwR (blue lines) mice exposed to 30 s, 460 nm stimuli over a range of irradiances. Four presentations of each stimulus were separated by a 300 s interstimulus interval. Number to left of each trace indicates irradiance as a log10 proportion of the brightest pulse (15.8 log10 photons/cm2/s). B, A plot of mean ± SEM firing rate 20–30 s after stimulus onset as a function of irradiance confirms the ability of all genotypes to show sustained firing at higher irradiances. C, Mean ± SEM firing rate above prestimulus baseline in Opn4−/− mice exposed to MWS-isoluminant 460 nm (blue trace) and 600 nm (orange trace) stimuli confirm the existence of a short-wavelength-sensitive sustained component to the PON response in this genotype. Numbers to left of traces depict irradiance as a log10 proportion of the brightest stimulus (14.2 log10 MWS opsin-effective photons/cm2/s). Subtracting 600 nm from 460 nm responses (solid black line) reveals a short-wavelength-specific response component at higher irradiances that shows little decay over 30 s of light exposure. D, Mean firing rate above prestimulus baseline for sustained cells in the PON around the end of a 30 s pulse. Left to right, rd/rd cl 460 nm, Opn1mwR 655 nm, Opn1mwR 460 nm, Opn4−/− 460 nm, and Opn4−/− 600 nm responses. Numbers to left depict log10 irradiance relative to brightest stimuli (15.8, 15.3, and 15.6 log10 photons/cm2/s for 460, 600, and 655 nm, respectively). Recordings at each irradiance across all genotypes and wavelengths were isoluminant for MWS or, in the case of Opn1mwR mice, LWS opsin. Dashed line represents baseline firing rate. Note the strong inhibition at lights off in the conditions expected also to activate S-cones (460 nm irradiances above −2 in Opn1mwR and Opn4−/− mice). Opn1mwR, n = 151 sustained cells from 6 animals; Opn4−/−, n = 68 sustained cells from 6 animals; rd/rd cl, n = 63 sustained cells from 8 animals.