Painful Heat Reveals Hyperexcitability of the Temporal Pole in Interictal and Ictal Migraine States

Abstract

During migraine attacks, alterations in sensation accompanying headache may manifest as allodynia and enhanced sensitivity to light, sound, and odors. Our objective was to identify physiological changes in cortical regions in migraine patients using painful heat and functional magnetic resonance imaging (fMRI) and the structural basis for such changes using diffusion tensor imaging (DTI). In 11 interictal patients, painful heat threshold + 1°C was applied unilaterally to the forehead during fMRI scanning. Significantly greater activation was identified in the medial temporal lobe in patients relative to healthy subjects, specifically in the anterior temporal pole (TP). In patients, TP showed significantly increased functional connectivity in several brain regions relative to controls, suggesting that TP hyperexcitability may contribute to functional abnormalities in migraine. In 9 healthy subjects, DTI identified white matter connectivity between TP and pulvinar nucleus, which has been related to migraine. In 8 patients, fMRI activation in TP with painful heat was exacerbated during migraine, suggesting that repeated migraines may sensitize TP. This article investigates a nonclassical role of TP in migraineurs. Observed temporal lobe abnormalities may provide a basis for many of the perceptual changes in migraineurs and may serve as a potential interictal biomarker for drug efficacy.

Autonomic dysfunction and migraine: Assessed by time series analysis of heart rate variability

“…The reduced cardiac vagal modulation in the newly diagnosed migraine patients of the present series is shared by several groups of researchers [16][17][18][19][20] .…”

The role of BOLD-fMRI in elucidating migraine pathophysiology

“…Moulton and colleagues [27] have measured brainstem fMRI responses to noxious heat in migraine subjects, showing a reduced activity at the level of the nucleus cuneiformis, a component of brainstem pain modulatory circuits. After this work, similar experiments have been performed in migraine subjects and the same research group has shown an increased BOLD response of the anterior temporal pole in migraine subjects during the interictal period [28]. Similarly, during a moderate noxious stimulus we have demonstrated a significantly greater activation in the anterior cingulate cortex (ACC) and a significantly lower activation in the bilateral somatosensory cortex (SCC) during a severe noxious stimulus, in MwoA patients during interictal period compared to healthy controls (HC) [29].…”

Taking the headache out of migraine

“…52 2. Alterations in descending pain modulation are also inferred from brain imaging, 53,54 suggesting that in migraine, like in many chronic pain diseases, ascending nociception is facilitated by diminished inhibitory (or increased facilitory) systems. It is thought that these begin to functionally fail as migraine undergoes chronification.…”