Fig. 1. Fear memory was enhanced by propofol after FC training in mice.

a Diagram of fear conditioning (FC) training and fear conditioning test (FCT) patterns. b Freezing in response to the conditioned tone after the infusion of different doses of propofol. Propofol enhanced freezing at doses of 60 × 4 and 60 × 5 mg/kg but not 60 × 2 and 60 × 3 mg/kg (n = 16/group, one-way ANOVA, F (4, 75) = 11.66, p < 0.001, **p < 0.01). c Freezing in response to the conditioned tone after the infusion of vehicle or propofol at different time points after the conditioning. Propofol enhanced freezing at 0 and 30 min but not at 60 min or 90 min (n = 16/group, two-tailed unpaired t test, **p < 0.01). d Representative images of Western blots and quantification of c-Fos expression among the 4 groups (n = 10, one-way ANOVA, F (3, 36) = 18.82, p < 0.0001, *p = 0.030, **p < 0.01). e Representative images of c-Fos/DAPI immunofluorescence in BLA neurons after vehicle or propofol treatment; scale bar, 100 µm. f The number of c-Fos⁺ cells in the BLA in mice that were administered propofol after FC training was increased compared to that in trained mice administered the vehicle (n = 20/group, one-way ANOVA, F (3, 76) = 349.8, p < 0.0001, **p < 0.01). g Freezing was comparable across all groups during FC training (n = 16/group, Kruskal-Wallis test, p = 0.523). h Trained mice administered propofol showed enhanced fear freezing compared to those administered the vehicle (n = 16/group, one-way ANOVA, F (3, 60) = 75.48, p < 0.001, **p < 0.01). All data are presented as the mean ± SEM.