Figure 2. Social rewards activate DRN 5-HT neurons.

(a–c) Ca²⁺ signals associated with mating behaviour of male mice. A SERT-DRN^GCaMP6 male mouse mounted a female following the introduction of the receptive female into the home cage of the male (a). Heatmap of Ca²⁺ transients and average plots show that mounting a female resulted in significant increase of Ca²⁺ across multiple behavioural bouts of a male mouse (b) and for the entire test group (c, n=6 mice). Thick lines indicate mean and shaded areas indicate s.e.m. Red lines indicate significant increase (P<0.05; permutation test). (d–f) Ca²⁺ signals associated with male–male interaction. GCaMP signals were recorded when a test male performed chemoinvestigation of an intruder male. Same conventions as in a–c. n=7 SERT-DRN^GCaMP6 male mice in f. (g–i) Ca²⁺ signals associated with investigation of a neutral object. An inanimate dummy mouse was introduced into the home cage of a test male (g). n=7 SERT-DRN^GCaMP6 male mice in i.