Photomicrograph of the VTA of DBHcre-TdTomato mice transduced with the virus AAV1-ChR2-eYFP showing co-localization of DBH positive fibers (Tomato red staining) and ChR2 expressing fibers (eYFP green staining). The triple labelling has been reproduced on 13 mice. TH immunostaining (blue) showed DA neurons contacting the NE fibers from the LC
expressing the ChR2. Scale bars: left 100 µm, right 10 µm.