Fig. 2

Activation of CaMKII-positive neurons in the ACC decreases the mechanical threshold. a Schematic diagram of viral injection site (left) and optic cannula placement (right) in the ACC. b One example of the effects of blue light in a CaMKII-ChR2 expressing mouse (red) and an EYFP expressing mouse (black) in the von Frey test. c Pooled data for ChR2 and EYFP mice. On average there was a reduction in the mechanical threshold in the ChR2 group. The graph on the right plots the combined data for the two ON and three OFF episodes. There was a significant effect of laser light in the ChR2 group: Off: 4.90 ± 0.13 g, on: 4.12 ± 0.22 g; n = 18) but not in the EYFP group (off: 4.99 ± 0.22 g, on: 4.81 ± 0.22 g; n = 10) [p = 0.011 in virus and light interaction, two-way repeated measures ANOVA]. d Not all animals showed a decrease of the mechanical threshold during light activation. Out of 18 animals, 10 showed a decrease whilst 8 did not. e The overlapped pattern of ChR2 expression in each group