RecruitingDevice studyCranial Electrotherapy Stimulation and Brain Imaging for Gulf War SyndromeThe main goal of the proposed study is to critically evaluate a nonpharmacological and readily available therapy, cranial electrical stimulation (CES) using Alpha-Stim™, and to discover the brain function mechanisms underlying Gulf War Illness-related Headache and Pain (GWI-HAP) and treatment response to CES. For this objective, the investigators will employ an adaptive trial design as well as a neuroimaging technique using MRI, which has become the pre-eminent technique for assessing the integrity of brain function, connectivity, and organization in healthy brain and pathology.