Extended Data Figure 2. Role of the vomeronasal pathway in mounting behavior.

a, Mounting time for males with a sham surgery (Sham) or the VNO removed (VNOX) towards LPS-females (Sham, n=5 and VNOX, n=7; from 2 independent experiments). b-d, Virus encoding the anterograde trans-synaptic tracer (AAV₁-hSyn-Cre) was targeted to the accessory olfactory bulb (AOB) in Ai14 reporter mice that express tdTomato in a Cre-dependent manner (b). Representative images (c) and quantification (d) of trans-synaptically labeled tdTomato(+) neurons in BST, MEA, and COApm at the specified anterior-posterior axis (n=4; from 3 independent experiments). Scale bar=500μm. e-g, Virus encoding ChR2 (AAV₂-hSyn-hChR2-EYFP) was targeted to the AOB (e,f). Representative image of FOS expression in the COApm upon photoactivation of the AOB, from n=3 animals (g). Scale bar=500μm. h, These data are associated with Fig.1g. Number of FOS-expressing neurons in the vomeronasal pathway after interaction with PBS- or LPS-females. **P<0.01, ***P<0.001 and ****P<0.0001 calculated by unpaired two-tailed t-test (a), one-way ANOVA with Bonferroni’s post-hoc test (d) and two-way ANOVA with Sidak’s post-hoc test (h). Graph indicates mean ± s.e.m. p-values are described in the supplementary statistical information file.