Figure 1

Contextual fear memory and its association with H4K5ac in the hippocampus. (A) Scheme of the behavioral experiment. Mice were trained on contextual fear conditioning (CFC) on day 1 (FC Day 1), tested 24 hours later on day 2 (Test Day 2), or conditioned again immediately following the test (FC Day 2), and tested again 24 hours later on day 3 (Test Day 3). Hippocampi were collected either one hour following FC Day 1 or one hour following Test Day 3. (B) Fear memory was measured as the freezing response before and after the foot-shock (shock) on FC Day 1, after re-exposure to the context on day 2 (Test Day 2), and after re-exposure to the context on day 3 in fear-conditioned (FC; n = 12) and in non-fear-conditioned controls (Control; n = 11). (C) Quantitative analysis and representative immunoblots of H4K5ac levels in nuclear fractions from whole hippocampus in controls one hour after context on day 1 (Control, n = 4), one hour after CFC on day 1 (Day 1 After FC; n = 4), or one hour after the memory test on day 3 (Day 3 Test; n = 3). Samples derived for immunoblots were processed in parallel using actin for normalization and run on two different gels. Error bars indicate SEM. *p < 0.05, **p < 0.01, ***p < 0.001.