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. 2022 Jul 21;13:4039. doi: 10.1038/s41467-022-31728-z

Fig. 6. Optogenetic inhibition of DRN 5-HT neurons and instigation-heightened aggression.

Fig. 6

a Ex vivo slice patch-clamp recording of EGFP + 5-HT neurons in the DRN of Tph2-tTA::TetO-eArchT-EYFP transgenic mice. Yellow lines indicate yellow light illumination (Top: 1 min, bottom: 10 min). b, c Summarized data for the spontaneous firing and resting membrane potential (RMP) before (Pre), during (ON), and after (Post) the 1-min light illumination, which showed successful suppression of both firing and RMP (one-way repeated measures ANOVA with Geisser-Greenhouse correction, n = 5 biologically independent animals, firing rate: F(1.486,5.945) = 15.06, p = 0.0060 (b), RMP: F(1.028,4.113) = 70.22, p = 0.0010 (c), post hoc t test with Tukey’s multiple comparisons tests (two-sided)). d Expression of eArchT-EYFP in the DRN and median raphe nucleus. Optic fiber was placed into the DRN (scale bar 500 μm). The timeline of the experiment was exactly the same as in Fig. 3. e Duration of total aggressive behaviors in each session. Gray lines show each individual’s data (n = 10 biologically independent animals) and black line indicates average data (Mean ± SEM). f Summarized data for the duration of total aggressive behavior in each condition. The Inst test increased total aggressive behavior compared to RI test in both OFF and ON sessions (one-way repeated measures ANOVA, n = 10 biologically independent animals, F(2,18) = 28.04, p < 0.0001, post hoc t test with Tukey’s multiple comparisons tests (two-sided)). g–j Detailed behavioral analysis showed that optogenetic inhibition of 5-HT neurons did not block the pro-aggressive effect of social instigation, including attack bites (g Friedman test (two-sided), n = 10 biologically independent animals, Friedman statistic = 16.80, p < 0.0001, post hoc test with Dunn’s multiple comparison test (two-sided)), and tail rattles (h one-way repeated measures ANOVA, n = 10 biologically independent animals, F(2,18) = 29.20, p < 0.0001, post hoc t test with Tukey’s multiple comparison tests (two-sided)), and did not affect non-aggressive behaviors (one-way repeated measures ANOVA, n = 10 biologically independent animals, n.s. for both locomotion (i) and social contact (j)). k–o No effect of light stimulation was observed in the RI test on the duration of total aggressive behavior (k), frequency of attack bites (l), duration of tail rattles (m), locomotion (n), and social contacts (o) (Mann–Whitney test (k) or paired t test (l, m, n, o), all two-sided, n = 10 biologically independent animals, n.s.). Each bar represents mean value ± SEM, and gray line indicates each individual’s data. *p < 0.05, **p < .01, ***p < 0.001, ****p < 0.0001. Source data are provided as a Source Data file.