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. Author manuscript; available in PMC: 2014 Mar 18.
Published in final edited form as: Curr Biol. 2013 Feb 28;23(6):467–472. doi: 10.1016/j.cub.2013.01.053

Figure 3. Time is a critical parameter of the CS-US association that triggers the update of strong fear memory.

Figure 3

Schematic of the experimental design and (A) percentage of freezing (mean ± s.e.m.) to the CS during reactivation (React) with a longer CS-US interval (US@30s) than the one learned during training (US@10s) and during post-reactivation long-term memory test (PR-LTM) in rats infused in the LA with vehicle (white bars) or anisomycin (black bars). Freezing during reactivation was equivalent between groups. Rats given intra-LA anisomycin showed an impairment of memory during PR-LTM. (B, C, D) Temporal pattern of freezing during PR-LTM tests (mean ± s.e.m. in 3s bins), for rats non-shifted (B), shifted with a US delivered later (C) or shifted with a US delivered earlier (D) during reactivation. In all experiments, there was a significant effect of time (B:F(19,280)=4.62; C:F(19,260)=2.91; D:F(19,240)=4.45; # P<0.0001). Only when a change in CS-US interval was imposed during reactivation, the anisomycin produced a significant reduction of freezing (B:F(1,280)=2.24, n.s.; C:F(1,260)=234.7 and D:F(1,240)=1019.6; *P<0.0001). When anisomycin was infused after reactivation with a shifted CS-US time interval from 30 to 10s, the temporal pattern of freezing was different from vehicle controls (D: time x group interaction F(19,240)=3.50; + P<0.0001).