Figure 4.

Acute stress decreases the reward response intensity of DRN serotonin neurons. A, A heatmap showing the effect of acutely restraining on the Ca²⁺ signal intensity of DRN serotonin neurons. The same amount of sucrose was delivered for 60 trials, and the mouse was head-restrained during trials 21–40. B, Peri-event plot of the average Ca²⁺ signals to sucrose from the animal shown in A before, during, and after the trials with head restraint. Data are aligned to pump onset for liquid delivery. C, Population-level data showing the effect of head restraint on the response of DRN serotonin neurons (n = 7 SERT-DRN-GCaMP6 mice). Response amplitudes were normalized to those before head restraint for each individual mouse. D–F, The effects of a fearful context on the sucrose response of DRN serotonin neurons (n = 11 SERT-DRN-GCaMP6 mice). A total of 60 trials were recorded. After initial 20 trials of recording, a mouse was moved to a new chamber and given five random footshocks ∼10 min before the recording of 20 trials recording sucrose responses. The mouse was then returned to the initial recording chamber and a final 20 trials were recorded. Error bars in C and F indicate SEM. *p < 0.05; **p < 0.01; n.s., not significant; multiple comparisons after repeated-measures one-way ANOVA. Shaded areas in B and E indicate SEM. Red and blue colors in B and E indicate significant increases and decreases from the baseline, respectively (p < 0.05, multivariate permutation tests). See Figure 4-1.