• migraine;
  • chronobiology;
  • generator;
  • phase-plane;
  • time-series

Objective.—To examine circadian and menstrual patterns of migraine frequency in order to identify properties of the putative migraine generator.

Methods.—Analysis of circadian and menstrual migraine attack frequency distributions, using between-interval differences as estimates, at each time point, of the derivative of the equation that would, theoretically, model the observed oscillating functions.

Results.—Circadian and menstrual analyses exhibit many similarities that are consistent with a single migraine generator in the final common pathway for expression of the phenotype. These analyses are inconsistent with a role for cortisol or ACTH to be activators of the putative migraine generator, could be consistent with visual stimulation as a deactivator of the generator, and may also be consistent with a low threshold concentration of estradiol and/or progestagens as inactivators of the migraine generator.

Conclusions.—Analysis of time-series data using differentials uncovers some previously unidentified chronobiological properties of migraine, helps select amongst various candidate provocative factors, and suggests some properties of a putative migraine generator.