Study of the Glymphatic System in Migraine

Inclusion Criteria: For patients: • Diagnosis of migraine, by the ICHD-3 criteria; For both patients and healthy controls: * Age between 18 and 60 years; * Willing and able to comply with scheduled visits. Exclusion criteria For patients: * Overuse of acute medications for headache; * Continuous or daily headache; * Other primary headache disorders, with the exception of infrequent tension-type headache. For healthy controls: • Any subject with frequent tension type headache, migraine, cluster headache, other pain syndromes or neurological conditions. For both patients and healthy controls: * Allergy to nitroglycerin; * Major psychiatric disorders such as bipolar affective disorder and schizophrenia; * Cardiovascular diseases that contraindicated the use of nitroglycerin; * Intracranial hypertension; * Cerebral haemorrhage; * Cerebral trauma; * Pulmonary toxic oedema; * Closed angle glaucoma; * Anaemia; * Pregnancy and breastfeeding; * Aortic stenosis or significant hypotension (SBP\<90mmHg or \<100mmHg and symptomatic) precluding nitroglycerin administration; * Use of sildenafil; * Any person unable to lie still within the environment of the MRI scanner for the required period to perform the study; * Any person where MRI scanning is contraindicated (metal implants, pacemaker, claustrophobia, etc.); * Use of illicit drugs; * MRI head showing any brain pathology, such as space-occupying lesions; * Any person unable to understand and follow the instructions of the investigators.