Fig. 4.

Protein synthesis inhibition in LBA does not affect fear memory in the absence of memory reactivation. To confirm that the SOFC memories are consolidated at the time of reactivation, it is necessary to show that protein synthesis inhibition in the absence of memory reactivation has no effect. Rats underwent SOFC and then were given infusions of ANISO or aCSF into LBA. The next day, they received a LTM retention test in which CS2 and then CS1 were presented. Groups given ANISO and aCSF did not differ. Results were analyzed by two-factor ANOVA, with drug (aCSF, ANISO) and retention test CS (CS1, CS1) as the factors (retention test CS was a repeated measure). The ANOVA indicated that in the absence of stimulus exposure, there was neither a main effect of drug (P = 0.78) nor a CS × drug interaction (P = 0.46). There was a main effect of CS [F (1, 10) = 22.8; P < 0.001], indicating freezing was higher to CS1 than to CS2, a common occurrence in second-order conditioning studies (24–29). This experiment demonstrates that reactivation of the memory by an exposure to the CS is necessary for protein synthesis blockade to impair the memory.