In a previously validated mouse model of encephalopathy of prematurity in which IL1B is administered intra-peritoneally from postnatal days 1–514 (Fig. 1a), we verified that microglia were the predominant myeloid cell in the brain (Supplementary Fig. 1a, b) and that the blood-brain barrier remained appreciably intact, with increased expression of tight junction and adherens genes (Supplementary Fig. 2a-d). This evidence concerns the gene IL1B and Encephalopathy.