Intra-mPFC virus injection was performed under anesthesia as previously described [33]. Briefly, AAV9-CMV-Cre-GFP (referred to as AAV-Cre) containing the genes for Cre recombinase and green fluorescent protein (GFP), and control AAV9-CMV-GFP (AAV-GFP) containing the GFP gene alone with titers > 1 × 1012 vg/mL (UNC Vector Core, Chapel Hill, NC) were injected bilaterally into the mPFC (coordinates: AP = + 1.8 mm, ML = ± 0.4 mm, DV = − 2.6 mm from the bregma) of adult female Bdnfflox/flox mice (7 weeks old). A total volume of 0.5 μL adeno-associated virus (AAV) vectors (per side) was delivered at a rate of 0.10 μL/minute with a 33-gauge stainless steel injector connected to a UMP3 microsyringe pump (World Precision Instruments, Sarasota, FL). Additional 10 min were allowed for diffusion and prevention of backflow. Behavioral tests were performed 21 days after AAV injection. The injection sites and the Cre efficiency were verified in each animal at the end of the experiment. Mice with “untargeted” injections were excluded from statistical analysis.
