Pain processing in patients with migraine: an event-related fMRI study during trigeminal nociceptive stimulation

We explored the functional pattern of the pain-processing network in patients with migraine, in the interictal periods, during trigeminal noxious stimulation. Contact heat evoked potential stimulation induced thermal pain and functional magnetic resonance imaging were used to measure whole-brain activation in 16 patients with episodic migraine without aura and 16 age- and gender-matched healthy controls in response to a severe (53°C) noxious, a moderate (51°C) noxious, and a control (41°C) stimulus applied to the maxillary skin. When comparing the fMRI activation over the entire brain, patients with migraine, with respect to healthy controls, showed a significantly greater activation in the perigenual part of anterior cingulate cortex at 51°C and less activation in the bilateral secondary somatosensory cortex at 53°C. A group-by-stimulus interaction analysis revealed a region in the pons showing a divergent response in patients and healthy controls. Correlation analyses demonstrated that the pons activation correlated with higher headache-related disability in patients. Our findings demonstrate increased antinociceptive activity in patients with migraine, which may represent a compensatory reorganization to modulate pain perception at the same intensity of healthy controls.