Fig. 7: The beneficial effect of PF4 on cognition is neurogenesis-dependent.

a Experimental design of aged DCX^DTR mice receiving intravenous (i.v.) PF4 injections every third day for 24 days and subsequent testing in the active place avoidance (APA) task, with an additional 4 injections of diphtheria toxin (DT) beginning on day 18. b The number of DCX⁺ cells following DT treatment and APA testing. c PF4-treated mice (blue) improved during the APA task, whereas this effect was absent in all other groups, including when PF4-treated mice received injections of DT, specifically ablating adult neurogenesis. d PF4-treated mice showed a reduction in the number of entries into the shock zone, whereas mice in the other three groups did not improve. Improvements following PF4 treatment were observed in all parameters of the test, including the number of shocks received (e), entries into the shock zone per distance travelled (f), and time to first (g) and second (h) entrance into the shock zone, as well as the maximum time spent avoiding the shock zone (i). Saline n = 11 mice; Saline DT n = 9 mice; PF4 n = 12 mice; PF4 DT n = 12 mice. Bars represent mean ± SEM. Statistical analysis was performed using one-way ANOVAs with Sidak post hoc comparison to compare groups on day 5 and two-way repeated measures ANOVAs with Dunnett’s post hoc comparison to compare groups throughout the 5-day test. ANOVA result *p < 0.05, **p < 0.01, ***p < 0.001, Dunnett’s comparison Saline vs. PF4 ^#p < 0.05, PF4 vs. PF4 DT ⁺p < 0.05. Source data are provided as Source Data file.