A) Performance with a visible, marked platform on test Day 1 (Time: p < 0.0001, immune status and interaction: n.s.) and B) a hidden platform during cued acquisition training over 5 days (Time: p = 0.003, immune status and interaction: n.s.) show similar results for WT, Rag2−/− and Recon mice. 2-way RM ANOVA. C) Number of crossings over area of removed platform during the probe trial, p = 0.012. ANOVA, Tukey post hoc. D) No difference was detected in distance traveled during the probe trial. E) Representative tracings of the probe trials. Arrow marks target quadrant; small circle indicates where the platform had been previously placed. F) Average escape latency during reversal task trials (hidden platform moved to opposite quadrant) over two days (4 trials/day). Immune status: p = 0.028, time and interaction: n.s. 2-way RM ANOVA, Tukey post hoc. G) Representative tracings of the swim paths during Day 2 of reversal trials. Arrow points to the target quadrant; small circle marks the platform placement. WT: n = 6, Rag2−/−: n = 5, Recon: n = 5. * p≤ 0.05, ** p ≤ 0.01.