Fig. 2

Optogenetic manipulation of IC during behavioral tests. (A) Experiment timeline and experimental protocol summary; (B) Left—Illustrative representation of the optogenetic manipulation in the IC. Center—IC transfected neurons expressing the fluorescent marker after the control (n = 9), Arch (n = 7), or ChR2 (n = 7) AAVs injection. Right—Example of an optical fiber placement on IC. (C) An illustrative depiction of the open field test showing the positioning of the microphone at the center of the open field, with rats receiving light stimulation (light 470 or 512-nm light stimulation) via a patch cable connected to the implanted optical fiber. Rats were submitted to a pre-test stimulation for 10 min before the open field test. (D) Total number of 50-kHz USVs recorded during the pre-test stimulation protocol and (E) during the open field test. (F) Total locomotion (cm) traveled during the open field test. (G) Total number of grooming and (H) rearing behavior; (I) Illustrative representation of the experimental protocol during the bar test. The catalepsy time was measured during a baseline period (no light stimulation) and during a test period (light stimulation using a 473-nm or 512-nm stimulus for optogenetic stimulation and inhibition, respectively); (J) Catalepsy time during the bar test is represented by the step-down latency (s). Data are expressed as mean ± SEM. Individual subjects’ data are represented by circles. *P < 0.05 and ***P < 0.001 compared to the ChR2 group, Dunn’s post hoc test after Kruskal-Wallis ANOVA.