Fig. 5

Chronic ventricular diffusion of LPS at low-dose induces partial dysregulation of food-reward behaviours. The mice were monitored for 5 weeks on the CT or HFD diet after stereotaxic cannulation and mini-pumps filled with saline solution (NaCl) or LPS implantation. (A) Experimental plan for Experiment 5 (n = 8–9/group). (B) 2-Food choice paradigm: HFHS diet-based food intake in grams by CT_NaCl, CT_LPS and HFD_NaCl mice (n = 6/group). (C) Operant conditioning test showing the number of active lever presses during the four progressive ratio (PR) sessions and (D) the breakpoint during the PR4 session by CT_NaCl, CT_LPS and HFD_NaCl mice (n = 6/group). The data are shown as the means ± SEMs. P values were obtained after one-way ANOVA followed by the Holm‒Sidak test (B, D) and after two-way repeated-measures ANOVA followed by Bonferroni post hoc correction (C). Different letters indicate significant differences at p values < 0.05 between CT_NaCl, CT_LPS and HFD_NaCl. ***: p value < 0,001 between CT_NaCl and HFD_NaCl