Fig. 5. Laser-light exposure in eNpHR3.0-expressing rats is sufficient to reduce neuronal activity in the dCA3 during reconsolidation.

A Timeline for experiment 5. Following cocaine self-administration and extinction training, eNpHR3.0-expressing rats received a 15-min memory-reactivation session, immediately followed by Laser-ON (n = 6) or Laser-OFF (n = 5) treatment for 1 h. Brain tissue was collected immediately after the optogenetic manipulation. The density of c-Fos-immunoreactive (IR) neurons was quantified in the areas indicated by the blue and red rectangles on the brain schematic on 10x and 40x images, respectively. B Representative 10x photomicrographs of the dCA3 stratum lucidum (SL) and stratum pyramidale (SP) of rats in the Laser-OFF and Laser-ON groups. Images showing DAPI staining (blue) were used to visualize SL and SP boundaries (see also Fig. S1), and corresponding overlay images were used to visualize eNpHR3.0-eYFP expression (green) and c-Fos immunoreactive (IR) cell bodies (red, arrows). C c-Fos-IR cell body density (mean ± SEM) in the SL and SP of rats in the Laser-ON and Laser-OFF groups. Symbols: *t-tests, ps < 0.05. D Representative 40x photomicrograph illustrating a GAD67 + c-Fos-IR cell body (arrow) in the dCA3. E GAD67 + c-Fos-IR cell density (mean ± SEM) in the dCA3 SL and SP of rats in the Laser-ON and Laser-OFF groups. Symbols: *t-tests, ps < 0.05. F Representative 40x photomicrograph illustrating a CaMKII+c-Fos-IR cell body (arrow) in the dCA3. G CaMKII+c-Fos-IR cell density (mean ± SEM) in the dCA3 SP of rats in the Laser-ON and Laser-OFF groups. Symbol: *t-test, p < 0.05.