Fiber photometry

Mice were unilaterally injected with 0.3 μL of AAV-syn-GCaMP7f and 0.2 μL of AAV-syn-NICD-shRNA-mCherry or control into the ipsilateral mPFC. A unilateral optical fiber (200 μm core, 0.39 numerical aperture (NA), RWD, China) was implanted at these coordinates and secured in place using dental cement after two weeks of recovery from AAV-micro-injection. Then, the mice recovered in their home cage for seven days before beginning behavioural testing. A fiber photometry system (R810, RWD Life Science, China) was used to record the fluorescence signal (GCaMP7f), which was produced by an exciting laser beam from 470 nm LED light and 410 nm LED light [39]. On the experimental day, mice were allowed to acclimate in the behavioural testing chamber for 30 min. After the acclimation period, baseline fluorescence was recorded for 5 minutes. Then, the mice were injected with METH (1 mg/kg, i.p.) or saline. Fluorescence was then recorded with the optical fiber for 15 min after the administration of METH. ΔF/F was calculated according to (470 nm signal-fitted 410 nm signal)/ (fitted 410 nm signal). The standard Z score calculation method was performed in MATLAB 2014. The formula was as follows: Z score = (x-mean)/std, x = ΔF/F.