IL1B and infection: These include intraventricular (Oitzl et al., 1993) and hippocampal (Barrientos et al., 2002) IL-1 administration, multiweek elevation of IL-1β in the hippocampi of transgenic mice (Hein et al., 2010), and elevation of endogenous IL-1β evoked by infections (Gibertini et al., 1995; Barrientos et al., 2006; Chen et al., 2008) or psychological stressors (Pugh et al., 1999).