Fig. 4.

Normal memory extinction following contextual fear conditioning in 5XFAD mice at <4 months of age. A, 5XFAD mice and their wild-type littermate mice were trained with one CS-US pairing for contextual fear conditioning. Mice were subjected to a single 30-min re-exposure to the conditioning context 1 day after training. Levels of freezing are plotted every 6 min through the 30-min extinction session. 5XFAD mice as well as wild-type control mice exhibit significant reductions in contextual freezing within the extinction session. B, Both wild-type and 5XFAD mice show significantly lower levels of freezing during the test session given 1 day after the 30-min re-exposure, as compared with the first 6-min of extinction session (n = 7–9 mice per group). * P < 0.05 versus the first 6-min of extinction. All data are presented as mean ± SEM.