A. Schematic of the preparation for opto-Pavlovian task combined with orexin promoter GCaMP recordings in the LH. B. Coronal image of a mouse brain slice infected with AAV-hSyn-DIO-ChrimsonR-tdTomato in the VTA and AAV1-hOX-GcaMP6S in the LH (left. Scale Bar; 1mm). White dashed lines indicate fiber tracts. Zoom of infected LH with AAV1-hOX-GcaMP6s and co-localization orexin IR and GcaMP6s (right. Scale Bars; 50 μm). C. Orexin promoter GcaMP recordings in the LH of a representative mouse around the laser-paired cue presentation at session 1 (left), grouped data (middle) and recordings during non laser-paired trial (right). D. Orexin promoter GcaMP recordings in the LH of a representative mouse around the laser-paired cue presentation at session 10 (left), grouped data (middle) and recordings during non laser trial (right). E. Area under the curve (AUC) of hOX-GcaMP signal in the LH around the cue presentations (0-1.5 seconds) across sessions. Laser-paired cue triggered bigger transient than non-laser paired cue. 2-way repeated measures ANOVA. Session, F9, 27 = 4.438, P=0.0012. Cue, F1, 3 = 25.41, P=0.0151. Interaction, F9, 27 = 4.125, P=0.0020. Tukey’s multiple comparison, *p<0.05, **p<0.01,***p<0.001 and ***p<0.0001. F. Orexin promoter GCaMP recordings during stimulation trials (left) and omission trials (middle and right). AUC around the omission was higher than baseline. One sample t test; t=4.693, df=3.P= 0.0183. n=4 mice.