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. Author manuscript; available in PMC: 2009 Dec 15.
Published in final edited form as: Nature. 2008 Dec 31;457(7227):281–287. doi: 10.1038/nature07682

Figure 5.

Figure 5

Flash threshold for modulation of ipRGC spike frequency. Loose-patch recordings from an in situ ipRGC at 35° C. a, Left, spontaneous firing in darkness. Right, a single spike from Left on expanded abscissa. b, Effect of different-intensity flashes (50 msec, 480 nm, 40-μm diameter spot centered on soma). Flash monitor at bottom. Relative flash intensity indicated on right of each trace. 40-pA scale bar for all traces except relative intensity “2,” where it is 10 pA due to a transient decrease in contact resistance with the cell. c, Peri-stimulus time histograms for flash intensities in b. 4–15 trials averaged, 500-ms bins. Threshold modulation of spike frequency occurs at relative flash intensity “4,” or 1.9 × 104 photons μm−2.