following coordinates: AP: −3.3 mm from bregma; ML: ±1.1 mm from midline; DV: −3.6 mm, −3.0 mm and −2.4 mm from brain surface3. For habenular injections in mice, the needle was angled 20° toward midline, and bilateral injections (0.375 μl each) were administered at a rate of 0.375 μl per min. For habenular injections in rats, the lentivirus was injected bilaterally based on previously published coordinates4. The incisor bar was set to 5 mm above plane, and the injector needle was at a 10° angle toward midline (AP: −2.2 mm from bregma; ML: ±1.5 mm from midline; DV: −4.9 mm from brain surface). The bilateral injections (1 μl each) were administered at a rate of 1 μl per min. For all of the injections, the injector needle was remained in place for a minimum of 2 min post-injection. For IPN and VTA microinjections in rats, guide cannula (Plastics One) were implanted as follows: IPN (flat skull; 10° angle toward midline; AP: −6.72 mm from bregma; ML: ±1.6 mm from midline; DV: −6.5 mm from brain surface) or VTA (bilateral; flat skull; 6° angle toward midline; AP: −5.4 mm from bregma; ML: ±1.3 mm from midline; DV: −7.0 mm from skull)3.
