Mice were anaesthetized with a mix of 1%–1.5% isofluorane and oxygen (1 l.min-1), while body temperature was monitored and maintained at 33°C using a temperature controller (ATC1000, World Precision Instruments). Unilateral injection of 300 nL of AAV5-αCaMKII-GCaMP6f-WPRE-SV40 (titer: 2.43 × 1013, Penn Vector Core) into the right Anterior Cingulate Cortex (AP: +1.0 mm; ML: +0.45mm; DV: −1.4mm) was performed using a Nanojet II Injector (Drummond Scientific, USA) at a rate of 4.6 nL per pulse, every 5 s. Injection pipette was left in place 20 min post-injection before removal. 25 minutes after injection, a 1mm diameter circular craniotomy was centered at coordinates (AP: +1.0 mm; ML: +0.55mm) and a 1mm GRIN lens (Inscopix) was implanted above the injection site at a depth of −1.2 mm ventral to the surface, and secured to the skull using cyanoacrylate (Loctite) and black dental cement (Ortho-Jet, Lang Dental USA). One 1/16-inch stainless-steel screw (Antrin miniatures) was attached to the skull to secure the cement cap that fixed the lens to the skull. Mice were then given an i.p. injection of buprenorfin (Bupaq, 0.1 mg.kg-1) and allowed to recover from anesthesia in a heating mat before returning to home cage.
