Fig. 7: Cognitive deficits in App^NL-G-F rats.

WT and App^NL-G-F male rats of 5 months old were used for behavioral experiments. a–c Horizontal locomotor activity measured using the open field test. Locomotion within 10 min after habituation was measured: (a) total distance traveled; (b) time spent in the central area; (c) the number of entries to the central area. n = 9/group. Note that the Homo rats appeared to avoid the center area. d, Motor coordination using rotarod test. The time on the rotarod before the rat fell was recorded. n = 9/group. e–h Spatial learning and memory. WT and Homo rats were subjected to learning paradigm of water maze for 4 days (e, f), followed by a probe trial at day 5 (g, h). Escape latency (e) and distance (f) of learning trials. Probe tests were conducted to evaluate spatial memory. The times spent in each quadrant (g) and entries of each quadrant (h) of probe trials are presented. n = 8–9/group. Statistics: two-way RM ANOVA for spatial learning, and t-test for probe test. i–k PAL test. WT and Homo rats (n = 9) were subjected to PAL test for 30 days with 100 trials per day after pretraining and training. i Touchscreen objects and locations. The animals were trained to associate three different stimuli (hollow circle, solid circle and cross) with three specific locations (left, center and right) (upper). There were all together 6 trial types in the PAL task (lower). j Time (days) to criterion in pre-training stage of 5 different phases. No difference was found between WT and Homo rats. k Mean percentage of correct response in testing stage. Each block represents 5 consecutive testing days. Statistics: two-way RM ANOVA with LSD post hoc, significant genotype and time interaction effect, *P < 0.05; **P < 0.01, compared with WT group. Note that the WT rats performed significantly better than the App^NL-G-F rats.