Endogenous memory content can be updated by natural events (such as water deprivation) during reconsolidation. Graphs show the mean ± SEM of percentage freezing time. The open field (OF) graph shows the mean ± SEM of the numbers crossing. Experimental design is depicted at the top of each panel. (A) The water-deprived group shows a significant decrease of memory expression during test 1, a phenomenon which is reverted by being water deprived again during test 2 (control group n = 10, water deprived n = 11). (B) When the reactivation session is omitted, water deprivation has no effect (control group n = 8, water deprivation n = 6). (C) Nimodipine injection before reactivation prevents the effect of water deprivation upon memory reconsolidation (control group/vehicle n = 7, control group/nimodipine n = 8, water deprivation/vehicle n = 10, water deprivation/nimodipine n = 11). (D) Water deprivation during 18 h has no effects upon motor performance (control group n = 7, water deprivation n = 8). Groups marked with the same letter (e.g., “a”) are statistically equal to each other and different from those marked with different letters (e.g., “a” groups differ from “b” groups), with significance level of P < 0.05.
