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. Author manuscript; available in PMC: 2015 Nov 1.
Published in final edited form as: Nat Med. 2015 Apr 27;21(5):476–482. doi: 10.1038/nm.3851

Figure 6. In vivo prosthetic stimulation and visual acuity.

Figure 6

(a) VEP modulation by irradiance and (b) by pulse duration under full field illumination (n = 9 WT animals and n = 7 RCS animals). (c) Sample VEP traces corresponding to different grating stripe widths. We defined the VEP amplitude as the peak-to-peak variation of the signal during the first 100 ms following grating alternation (gray shaded area) for prosthetic stimulation. Visible light triggered slower and longer-lasting responses and we measured the amplitude during the first 300 ms after alternation. Responses decreased to the noise level with 50 μm stripes. (d) VEP amplitude for visible gratings (blue) and prosthetic stimulation (red) decrease with decreasing width of the stripes. Acuity limit and its associated uncertainty, estimated as the crossing point of the parabolic fits with the noise level (dashed lines), corresponds to 27 ± 9 μm/stripe for visible-light and 64 ± 11 μm/stripe for prosthetic stimulation (n = 7 WT animals with visible light and n = 7 RCS animals with prosthetic stimulation). Error bars show standard error of the mean. NS: not significant; *: P < 0.05; ** : P < 0.01 : ***: P < 0.001, one-tailed Welch t-test.