In patients known with migraine without aura a migraine headache or migraine like headache will be induced by infusion of calcitonin gene related peptide (CGRP). The patients will then be stimulated with noxious heat via a thermode placed at the forehead. At the same time the Blood-oxygenation-level-dependent (BOLD) response will be measured via functional magnetic resonance imaging (fMRI), to estimate the central-nervous pain response. The regions of interest (ROI) will be thalamic region and medulla oblongata.