PPP1R1B and Anxiety: While Egr1 shows a complex cyclical expression pattern across the oestrous cycle (Fig. 1b, Supplementary Data 1), its initial rise coincides with the rise in oestrogen in proestrus18, increased expression of its target gene Ppp1r1b (Supplementary Figure 1, Supplementary Data 1) and reduced anxiety-related behaviour, as evidenced by increased time spent in the open arms of the elevated plus maze (EPM, Fig. 1c, Supplementary Data 1).