IL1B and injury: IL-1β-treated animals exhibited anxiogenic behaviours in the light–dark box, indicating that this model of preterm brain injury can induce an anxiety phenotype (Fig. 5D–F); the frequency of the animals in the light zone (SAL: 29.4 ± 2.0, IL1: 19.8 ± 1.3), as well as the number of transitions between the light and dark zones (SAL: 58.0 ± 3.9, IL1: 38.5 ± 2.7), were significantly decreased.