Fig. 2.

Experimental design and approach. (A) Animals were transferred to the custom fear conditioning home cages 3 days prior to fear conditioning, to allow Venus decay from handling and novel environment. On day 3, animals were exposed to either 9 tone-shock pairings or 9 shocks, and then euthanized 6 h later. (B) Arc+ neurons in the BLAp were identified, and both Arc+ and neighboring Arc− neurons were iontophoretically filled with Lucifer Yellow for imaging and spine morphology analysis (C).