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. Author manuscript; available in PMC: 2018 Jun 15.
Published in final edited form as: Biol Psychiatry. 2016 Oct 21;81(12):1041–1049. doi: 10.1016/j.biopsych.2016.10.018

Figure 9.

Figure 9

RMTg signaling to the ventral tegmental area (VTA) is essential for both the encoding of punishment and the decision to engage in the punished response. Rats expressing the inhibitory opsin Arch (AAV2-hSyn-eArch3.0-EYFP) or control vector (AAV2-hSyn-EYFP) were tested in the progressive shock task while simultaneously undergoing inhibition of RMTg axons in the VTA at discrete time points. (A) Representative images of RMTg virus expression and optical fiber placement in the VTA. (B) A timeline of the experiment. (C) Actual shock breakpoints between vector conditions during desynchronized/synchronized light presentation. (D) Optical inhibition of RMTg terminals in the VTA coinciding with footshock (synchronized) caused a significant increase in shock breakpoint relative to sessions in which light was delivered before/after footshock (desynchronized)(n=9). Similarly, (E) optical inhibition at the time leading up to the food-seeking response (decision phase) significantly increased shock breakpoint relative to sessions in which no light was delivered. Notably, we found no effect of light administration in rats expressing control vectors (n=5, 6). *p<0.05