Fig. 4

Effects of germ-free status on the expression of neuropeptide receptor genes implicated in social behaviour. Data are plotted as mean expression (relative to the control group) ± SEM for Oprm1, Oxtr and Avpr1a (encoding the µ-opioid, oxytocin and vasopressin receptors respectively) and all comparisons are with n = 8 per group. Two-sample t-tests have 14 degrees of freedom (df) and asterisks denote P < 0.05