Figure 1

Effects of elPB inactivation on the acquisition of auditory-conditioned fear. A, Experimental schedule. B, Pseudo-color plots showing the instantaneous freezing ratio of an individual mouse during the retrieval tests following conditioning with CS1 (Day 2; left panel) and CS2 (Day 4; right panel) in the MUS group (n = 10, top), the drug control (n = 10, middle), and the placement control (n = 9, bottom). The orange and purple horizontal bars indicate the period in which the auditory cue was delivered for CS1 and CS2, respectively. C, D, Summary of freezing ratios during the first 30 s after the animal was placed in the retrieval chamber (baseline) and during the first 30 s after the onset of CS presentation. The mean ± SEM values for the three groups are shown with open circles representing the values obtained from each mouse. In the CS1 retrieval test, the freezing ratio was significantly lower in the MUS group than that in the two control groups. There were no significant differences in freezing ratio between the placement and drug-control groups (C). The CS2 retrieval test revealed a significant increase in freezing ratio without any significant between-group differences (D). E, The CS1/CS2 freezing ratio was calculated as CS1 freezing time divided by CS2 freezing time during the first 30 s after the onset of CS presentation in individual mice. The CS1/CS2 freezing ratio was significantly lower in the MUS group than that in the control groups. There were no significant differences in CS1/CS2 freezing ratio between placement and drug control groups (*p < 0.05, **p < 0.01, ANOVA and post hoc Tukey’s HSD test).