Fig. 4

Effects of simvastatin withdrawal on hippocampal cholesterol levels, memory behaviors and hippocampal LTP. a Representative images and normalized intensity of hippocampal cholesterol in the vehicle (Veh)- and simvastatin (Simv)-treated mice and the mice with simvastatin discontinuation (Dis). n = 6 per group. Scale bar: 1 mm. b Average values of time the different groups of mice spent in exploring the familiar (F) and the novel objects (N) in the NOR tests. n = 6–8. c Latency of the different groups of mice in finding the platform in the MWM tests. n = 8 per group. d Average values of time the different groups of mice spent in the target quadrant and the other three quadrants (opposite, right and the left) during the probe test. n = 8 per group. e Distance travelled of the different groups of mice in finding the platform in the MWM tests. n = 8 each group. f Average values of swimming speed of the different groups of mice. n = 8 per group. g Left: representative traces of fEPSPs evoked in the CA1 by electrical stimulation of the Schaffer-commissural projection before and after HFS stimulation in the different groups of mice. Right: time course of fEPSP slope normalized to baseline. The fEPSP slope is plotted as a percentage change against the baseline (20 min) before HFS. HFS is indicated by arrows. n = 6 from 3 mice. h Normalized fEPSP slope (as a percentage of the baseline) in the hippocampus CA1 of the different groups of mice. n = 6 from 3 mice. Data are represented as mean ± SEM. *P < 0.05 based on unpaired t tests; ns, not significant (P > 0.05)