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. Author manuscript; available in PMC: 2014 Sep 1.
Published in final edited form as: Nat Biotechnol. 2014 Feb 16;32(3):274–278. doi: 10.1038/nbt.2834

Figure 2.

Figure 2

Transdermal illumination of AAV6-hSyn-ChR2-eYFP-injected mice results in tunable pain-like behavior and sensitizes mice to mechanical and thermal stimuli. a) Experimental schematic b) AAV6-hSyn-ChR2-eYFP or AAV6-hSyn-eYFP (YFP) was injected into the sciatic nerve unilaterally. Latency in withdrawal response to blue light (at indicated times after injection) or yellow light (2–4 weeks after injection) (1 mw/mm2, n = 4 mice) was measured. (*, One-way ANOVA: F(6,21) = 3.98; P = 0.0082; Dunnett’s test: P (week 2) = 0.034, P (week 3) = 0.027, P (week 4) = 0.026; effect size (week 2) = 2.10, effect size (week 3) = 2.17, effect size (week 4) = 2.19). c) Mice were injected as in (b), except bilaterally, and exposed to blue light of varying intensity. 2–4 weeks after injection, latency in withdrawal response was measured (n = 4 hind paws from 2 mice). d) Place aversion schematic e) Change in preference of AAV6-hSyn-ChR2-eYFP (ChR2; 55.6% decrease in time spent in blue-lit areas, effect size = 3.11, P = 0.0013, n = 5) or AAV6-hSyn-eYFP (YFP; 19.9% increase in time spent in blue-lit areas, P = 0.06, n = 5)-injected mice for the blue-lit areas was measured 2–4 weeks after injection during exposure to light. These two percent changes were statistically different from each other. (P = 0.00061) f) Place aversion changes compared to baseline (no light). g) Traces of individual mice for place aversion data. h) Schematic of experiment assessing ChR2-mediated sensitization (0.25 mW/mm2 blue light intensity) to von Frey filaments. i) von Frey thresholds in AAV6-hSyn-ChR2-eYFP-injected mice (effect size = 0.904, P = 0.027, n = 10 paws) and wild-type uninjected mice (P = 0.50, n = 10 paws) in the presence and absence of blue light. j) Schematic of experiment assessing optogenetic modulation of thermal thresholds. Blue light power density (0.15 mW/mm2). k) Withdrawal (Hargreaves) latency to infrared stimulus in AAV6-hSyn-ChR2-eYFP-injected mice (effect size = 2.77, P = 0.00038, n = 7 paws) and wild-type uninjected mice (P = 0.91, n = 9 paws, controls for ChR2 injected mice) in the presence of blue light or off-spectrum control illumination. All grouped data are shown as mean ± s.e.m.