Figure 2.

Fear extinction fails to reverse fear conditioning-induced suppression of excitability in IL-mPFC layer 5 pyramidal neurons of adolescent mice. A) Average freezing during exposure to tone alone or tone-shock pairing on day 1, during extinction training on day 2 and fear memory test on day 3. B) Example traces of voltage responses to hyperpolarizing (−50 pA) and depolarizing (+200 pA) current steps in pyramidal neurons from tone alone, fear condition and fear extinction groups. Scale: 250 ms/20 mV. C) Current vs. action potential (AP) frequency plot in tone alone (18 neurons/5 mice), fear condition (19 neurons/5 mice) and fear extinction (13 neurons/5 mice) groups. The fear condition group showed fewer action potentials compared to tone alone group and this effect remained unaffected by fear extinction.