Figure 1. PSD-95 deletion does not affect retrieval of recent fear memories, but impairs their extinction and precision.

(a) Schematic of experimental design for testing recent fear memory retrieval following delay conditioning. (b) Genotypes showed equivalent levels of freezing during cue and context retrieval (n=11–17). (c) Schematic of experimental design for testing recent fear memory retrieval following trace conditioning. (d) Following trace fear conditioning, genotypes showed similar cue fear retrieval, but PSD-95^GK mice froze significantly less than wild-type controls during context retrieval (n=8–10). (e) Schematic of experimental design for testing extinction of a recent fear memory. (f) WT controls, but not PSD-95^GK mice, decreased freezing from the first to the last extinction trial-block, and froze less during extinction retrieval as compared to the first trial-block of extinction training (n=11). (g) Schematic of experimental design for testing the precision of a recent contextual fear memory. (h) WT controls, but not PSD-95^GK mice, froze more to the conditioned context than either of two different contexts (n=13). Data are means ± SEM. *P<.05 vs. WT/Context, #P<.05 vs. 1st Ext-block/WT, †P<.05 vs. Ren/WT, ‡P<.05 vs. Context A/WT