Panic disorder (PD) is an acute paroxysmal anxiety disorder with poorly understood pathophysiology.The dorsal periaqueductal gray (dPAG) is involved in the genesis of PD.However,the downstream neurofunctional changes of the dPAG during panic attacks have yet to be evaluated in vivo.In this study,optogenetic stimulation to the dPAG was performed to induce panic-like behaviors,and in vivo positron emission tomography (PET) imaging with 18F-flurodeoxyglucose (18F-FDG) was conducted to evaluate neurofunctional changes before and after the optogenetic stimulation.Compared with the baseline,post-optogenetic stimulation PET imaging demonstrated that the glucose metabolism significantly increased (P ＜ 0.001) in dPAG,the cuneiform nucleus,the cerebellar lobule,the cingulate cortex,the alveus of the hippocampus,the primary visual cortex,the septohypothalamic nucleus,and the retrosplenial granular cortex but significantly decreased (P ＜ 0.001) in the basal ganglia,the frontal cortex,the forceps minor corpus callosum,the primary somatosensory cortex,the primary motor cortex,the secondary visual cortex,and the dorsal lateral geniculate nucleus.Taken together,these data indicated that in vivo PET imaging can successfully detect downstream neurofunctional changes involved in the panic attacks after optogenetic stimulation to the dPAG.