Figure 5.
Peptidergic neurons of the EW nucleus are required for preparatory nesting during pregnancy
(A) CART+ neurons specific lesion: brain sections immunolabeled for CART at different levels of the EWcp nucleus following an injection of an AAV1 virus carrying a loxed endogenously activated taCasp3-TEVp construct. The number of CART+ neurons is strongly reduced in CART-cre animals compared with injected WT controls.
(B) Proportion of brooding nests (left panels) in a cohort of WT or CART-cre mice lesioned for the EWcpCART+ neurons and evolution of the nest scores after mating (right panel). After mating, only 10% of lesioned animals build brooding nests reliably (more than 2/3rd of the time), compared with 78% of the unlesioned control animals. The nest scores of lesioned animals are lower in virgins and throughout pregnancy.
(C) Automated video tracking of nestlets interactions in WT or CART-cre animals injected with taCasp3-TEVp over 5 h.
(D) In virgin females, the cumulative curves of nestlets interactions in control and lesioned animals overlap and behavior switches are similar.
(E) In pregnant control females, the cumulative time interacting with nestlets increases compared with virgin controls but not in lesioned females. Behavior switches throughout the session: the weight of the arrows is proportional to the number of times the mouse switches between two behaviors. In pregnant lesioned mice, the alternation between nesting and general activity is reduced compared with pregnant controls.
(F) In primiparous mice exposed to pups, the nestlets interaction time is high in both control and lesioned mice (measured over 1 h). The ablation in Cart-Cre mice doesn't affect the transitions towards nesting in the presence of pups. Scale bars are 150 μm. ∗ P < 0.05 and ∗∗ P < 0.01. All data are presented as mean ± SEM. Unpaired Mann-Whitney ranked U test (A, B, and D-F). See also Figures S3–S5 and Video S3.