Developmental trends of PACAP immunoreactivity during the first 3 postnatal weeks in the PBC (A), Amb (B), XII (C), NTSVL (D), and CN (E). Tukey’s Studentized tests indicated a significant fall in immunoreactivity from P11 to P12 in the PBC and Amb, and from P10 to P12 in the XII and NTSVL. However, no significant changes were observed in the CN. *P < 0.05. (Modified from Liu and Wong-Riley, 2019).