Abnormal brain processing of pain in migraine without aura: a high-density EEG brain mapping study

In the present study we used high-density EEG brain mapping to investigate spatio-temporal aspects of brain activity in response to experimentally induced muscle pain in 17 patients with migraine without aura and 15 healthy controls. Painful electrical stimuli were applied to the trapezius muscle and somatosensory-evoked potentials were recorded with 128-channel EEG with and without concurrent induced tonic neck/shoulder muscle pain. At baseline, the calculated P300 dipole for single stimuli was localized in the cingulate cortex. In patients, but not in controls, the dipole changed position from baseline to the tonic muscle pain condition (z = 29 mm vs. z = -13 mm, P < 0.001) and from baseline to the post-tonic muscle pain condition (z = 29 mm vs. z = -9 mm, P < 0.001). This may be the first evidence that the supraspinal processing of muscle pain is abnormal in patients with migraine without aura.