Figure 3

Imaging Cone Calcium in the Live Eye

(A) Confocal images of synaptically targeted GCaMP6f (green, Tg(opn1sw1:SyGCaMP6f)) in UV cones (magenta, Tg(opn1sw1:nfsBmCherry)).

(B) Mean and single trial dorsal and SZ single cone 2-photon calcium responses to varying duration light- (6 × 10⁵ photon/s/μm²) and dark-steps (0 photon/s/μm²) from a constant UV background (2.4 × 10⁴ photon/s/μm²).

(C) Mean calcium responses to the same stimulus as in (B) from ventral, nasal, dorsal, and SZ cones (V, N, D, and SZ; n = 9, 21, 23, and 29, respectively). Shadings represent ±1 SD. Left panel shows an enlargement of the response to the 20-ms light step.

(D) Mean and 95% confidence intervals of peak amplitudes from (C).

(E) Enlargement from (D). All responses except nasal and ventral 20-ms dark-flash conditions were significantly different from zero (Mann-Whitney U test). Within-condition pairwise comparisons across for SZ versus the other three zones are indicated with asterisks (^∗p < 0.05, ^∗∗ p < 0.01, and ^∗∗∗ p < 0.001, respectively; p value adjustment, Tukey method for comparing a family of four estimates).

(F) Light and dark responses from (C) and (D) plotted against each other for equivalent stimulus durations, with 95% confidence intervals indicated.

(G and H) Mean calcium responses to increasing-amplitude 5-ms light flashes from darkness, as indicated (G), and quantification (mean and 95% confidence intervals) with Hill functions fitted (H).

(I) Quantification of calcium responses as in (G) and (H) following horizontal cell (HC) blockage using CNQX. For better comparison, curves from (H) are added as faint dashed lines. n = 51, 29, 46, and 17 for SZ, D, N, and V, respectively, for control and n = 51, 32, 46, and 19 after HC block.