Typically, migraine is considered to be an episodic disorder with discrete attacks of headache. But new research by Dr. Till Sprenger and his team from UCSF Headache Group and Technische Universität München found increased network activity -- stronger functional connectivity -- bilaterally in the visual, auditory and sensorimotor network in migraineurs.

"There has been increasing evidence that the processing and perception of sensory stimuli is abnormal even outside of attacks," said Dr. Sprenger. "Now our findings underline that abnormal brain activity in migraineurs is not restricted to attacks -- that there is an extensive alteration of functional connectivity in multiple networks reflecting the migrainous phenotype, emphasizing that migraine is a disorder of the brain."

Findings are being presented at the American Headache Society's 52nd Annual Scientific Meeting in Los Angeles.

"This research has been anticipated for some time and is absolutely fundamental to our understanding of migraine," said David Dodick, M.D. president of the American Headache Society. "It is likely that the observed interictal abnormalities of brain activity and connectivity explains the predisposition to spontaneous attacks, as well as the vulnerability of migraineurs to a myriad of external and endogenous triggers. It may also explain the persistence of headache in some sufferers and the persistence of symptoms in between attacks of pain (e.g. sensitivity to light)."

More than 200 scientific papers and posters are being presented during the AHS meeting which is expected to draw some 500 migraine and headache health professionals including doctors, researchers, and specialists.