Hemodynamic correlates of mental arithmetic task in migraine

Abstract

Investigating the relationship between the hemodynamic changes and cognitive activity (known as the neurovascular coupling) provides a basis of the underlying physiology of the brain energy mechanisms. The aim of this study was to investigate the differences in the hemodynamic response caused by the mental arithmetic (MA) task between migraineurs and healthy subjects by using functional near infrared spectroscopy (fNIRS). 16 healthy subjects (5 male, 11 female) and 16 migraine patients (4 male, 12 female) participated in the study. Subjects were asked to perform mental subtraction and answer verbally to 3 sets of questions with increasing complexity. Performance, work load, FNIRS data and laterality (LI) index were analyzed. The difference in the oxyhemoglobin levels across different complexity levels were calculated. As the MA task got harder, work load increased, performance decreased and the change in [HbO2] increased for both groups but showing a lower incremental in oxy-Hb concentration in migraine patients for varying complexity levels. Control group showed a right dominant PFC activity, whereas migraine patients showed a left dominant PFC actvity. Our results support the hypothesis that migraine is a neurovascular coupling dysfunction causing unregulated activation in PFC than controls.|Keywords: fNIRS, migraine, mental arithmetic, laterality index, prefrontal cortex.