Figure 8.

Cued fear memory extinction was impaired in HPC-1/syntaxin 1A KO mice. Each mouse received CS–UCS pairings five times in a conditioning chamber. Approximately 24 h after pairing, each mouse received cued fear memory extinction trials in a novel test chamber. The extinction trials consisted of the CS for 57 s five times per day without the USC in a novel test chamber. The extinction trials were repeated for 4 d. The freezing response to the CS in each extinction trial was scored. Cued fear memory extinction in KO mice was impaired compared with WT and HT mice, although consolidation and retention of the memory was indistinguishable among all genotypes (WT, n = 8; HT, n = 8; KO, n = 8). *p < 0.01; **p < 0.005. Data represent mean ± SD.