Cerebral cortical activity in migraine: a LORETA analysis

Abstract

Abstract: 

INTRODUCTION:  Migraine patients exhibit electrophysiological alterations of cortical activity in relation to the phase of the disease. These abnormalities can be observed using different approaches, both under stimulation and at rest. Low Resolution Brain Electromagnetic Tomography (LORETA) is a noninvasive EEG-based neuroimaging technique that provides direct information about neural processes. 

OBJECTIVES: To evaluate cerebral cortical activity in episodic and chronic migraineurs compared to healthy controls using eLORETA.

METHODS: 1 minute of artifact-free wake resting state electroencephalogram epochs from 25 healthy volunteers and 74 migraineurs (25 ictal, 25 interictal and 24 chronic) were analyzed using eLORETA. Subject-normalized delta (1-3Hz), theta (4-7Hz), alpha (8-12Hz), beta (13-30Hz) and gamma (31-45Hz) band activities were contrasted between groups. In addition, activity from specific regions of interest (data-driven) was extracted to for statistical comparison.

RESULTS: Differences in resting state activity were consistently found in the subcallosal (BA25), parahippocampal (BA28, BA34, BA35, BA36) and precuneus (BA7) regions. A multivariate statistical comparison revealed significant differences for the group-region-frequency band interaction.

CONCLUSIONS: Electrophysiological features of resting state cortical activity differ between migraineurs and healthy controls.  Differences are localized in a handful of regions, some of which have been previously related to the condition using other methods in the past. In comparison with other neuroimaging tools, eLORETA directly assesses cerebral activity and not indirect markers, such as blood flow or metabolism. Furthermore, band-specific findings may provide additional information referring to different levels of neural hierarchy. Additional research is warranted in order to better understand the pathophysiological implications of these findings.