Figure 4: The covert retrieval of a contextual fear memory results in labile memory trace that is vulnerable to disruption by protein synthesis inhibition.

(a) Behavioral schematic. (b) Representative photomicrograph depicting bilateral dHPC cannula placements. (c) Documentation of cannula placements in the dHPC. Symbols denote the location of the injector tips of the cannula tracts for each animal for each group³⁵. (d) Freezing behavior during conditioning, reactivation, and the context test. For conditioning, the left panel depicts the mean percentage freezing for each group during the 5-min baseline period (BL) and across each conditioning block. For reactivation, the panel depicts freezing during 3-min baseline (BL) period and across one retrieval trial (the trial consisted of one 10-s CS and the 60-s post-tone interval). Administration of rapamycin into the dHPC immediately after presentation of a BW, but not FW, CS impaired freezing behavior during the subsequent drug-free context test. The right panel depicts average freezing across the entire 20-min context test for each group (BW-VEH vs. BW-Rapa, p = 0.006), two-way analysis of variance (ANOVA) followed by Bonferroni’s multiple comparisons post hoc test. Groups: [FW-VEH (n = 15); FW-Rapa (n = 13); BW-VEH (n = 14); BW-Rapa (n = 11)]. All data are represented as means ± s.e.m.