Figure 7.

Amyloid deposition does not affect learning on a contextual discrimination task (Experiment 4). Mean ± SEM difference scores (percentage freezing in shock context − percentage freezing in safe context) across the three 3-d blocks of context discrimination trials. Although old/APP⁺ mice (filled squares) were not different from old/APP⁻ mice (filled circles), all old mice (filled symbols) were impaired at learning the discrimination as compared with the young mice (open symbols), which did not differ from one another. These results indicate that the deficiency among old mice in discriminating contexts is caused by overgeneralization of fear across contexts.