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. 2022 Aug 19;8(33):eabn9134. doi: 10.1126/sciadv.abn9134

Fig. 6. Optogenetic stimulation of the LC-LHA noradrenergic pathway suppresses feeding when stimulation is pulsed during the entire behavioral assay, but not when restricted to feeding events.

Fig. 6.

(A) Schematic illustration of coronal mouse brain shows location of Flp-dependent AAV used to drive ChrimsonR-tdT expression and location of fiber-optic probes. (B) Timeline of closed-loop optogenetic experiment wherein photostimulation (560 nm, 10 Hz, 10-ms pulses) was triggered upon pellet retrieval and occurred briefly for 10 s during consumption from the FED. (C and D) Left: Average feeding behavior of fasted mice during the closed-loop optogenetic experiment. Two-way repeated-measures ANOVA, stimulation × virus interaction: number of pellets consumed (C; F1,11 = 0.2807, P = 0.6068) and pellets retrieved (D; F1,11 = 1.857, P = 0.2003). Data are means ± SEM. n = 7 LC-LHAtdT mice and n = 6 LC-LHAChrimsonR mice. Right: Feeding behavior of fasted mice during closed-loop optogenetic experiment as percent change of photostimulation (On) from no stimulation (Off). Unpaired sample t test: percent change in pellets consumed (C; t11 = 0.8160, P = 0.4318) and pellets retrieved (D; t11 = 0.6549, P = 0.5260). (E) Timeline of FI during open-loop photostimulation (10 Hz, 10-ms pulses). (F) Left: Average 30-min food intake of fasted mice in the presence (On) or absence (Off) of open-loop photostimulation. Two-way repeated-measures ANOVA, stimulation × virus interaction: F1,12 = 5.116, P = 0.0431. Bonferroni post hoc test, *P < 0.05. Data are means ± SEM. n = 7 LC-LHAtdT mice and n = 7 LC-LHAChrimsonR mice. Right: Food intake during photostimulation (On) as a percent change from no photostimulation (Off). Unpaired sample t test, t12 = 2.269, *P < 0.05. (G) Ambulation in FI task during open-loop photostimulation. Left: Representative traces show ambulation, yellow circle indicates food cup location, and gray circle indicates location of an empty cup. Right: Average 30-min ambulation of fasted mice in FI assay during open-loop photostimulation. Two-way repeated-measures ANOVA, stimulation × virus interaction: F1,12 = 10.33, P = 0.0074. Bonferroni post hoc test, *P < 0.05.