All tests took place in mouse operant chambers (17.8 cm × 15.2 cm × 18.4 cm; Med Associates). A rotating optical commutator (Doric) was located on the top of the operant chamber and connected to a 473 nm diode-pumped solid-state laser (OEM Laser Systems; see Fig. 2f). Fibers were connected to the implants on the mouse for every training session. The conditioning chamber light was turned on during every training session. Laser power was adjusted to obtain ~10 mW transmittance into the brain. Mice were trained to nose poke in a MED Associates operant box with two nose-poke portals available, “active” and “inactive.” Successful nose pokes on the active nose poker rewarded the mouse with 2s of stimulation (40Hz, 10ms pulse width). An orange cue light turned on above the sipper during the 2s stimulation period. Nose poking to the inactive portal produced no consequences or rewards. Once discrimination was acquired during 1 h long FR1 sessions (less than 30% of total poking in the inactive hole), mice underwent 1 session of FR3. Mice’s motivation was then assessed using a 1 h session of progressive ratio schedule of reinforcement. The data were calculated as total number of nose pokes at the active and inactive for each day over the course of the experiment17 (link),64 (link).