The effect of painful laser stimuli on EEG gamma-band activity in migraine patients and healthy controls.

OBJECTIVE

Gamma-band oscillations (GBOs) induced by nociceptive stimuli were compared between migraine patients and controls in order to further characterize interictal pain processing in the brain of migraineurs. GBOs were related to subjective pain intensity, years of migraine history and migraine attack frequency and the sources of GBOs were investigated.

METHODS

Twenty-three migraine patients without aura and 23 controls received a series of laser stimulations on their right forehead and right hand while recording electroencephalographic data (61 electrodes). After each series they indicated the perceived pain. A multitaper time-frequency method was used on artifact-cleaned scalp data and frequency domain beamforming was used to localize the GBOs.

RESULTS

In both groups we observed increases in GBOs around central electrodes, which were not significantly different between groups. The central GBOs were positively associated with the subjective pain ratings in the control group, in accordance with previous studies, but not in the migraine group. Increases in gamma power were observed in the midcingulate cortex.

CONCLUSIONS

No evidence was found that GBOs differ between interictal migraine and controls nor that central GBOs represent a neurophysiological correlate of subjective pain in migraine.

SIGNIFICANCE

We shed light on observations of GBOs during pain processing in interictal migraine.