Researchers at Missouri State University's Center for Biomedical & Life Sciences found that REM (rapid eye movement) sleep deprivation caused increased expression of the proteins which are known to play an important role in initiating and sustaining chronic pain. REM sleep occurs in 90 to 120 minute cycles during the course of the night and is also thought to be involved in the process of storing memories, learning and balancing our mood. Dreaming often occurs in REM sleep . According to Dr. Durham, they approached the study because "previous clinical data support a relationship between sleep quality and migraine." The researchers used an established model of sleep deprivation to measure levels of proteins that lower the activation threshold of peripheral and central nerves involved in pain transmission during migraine. Their research shows that REM sleep deprivation leads to changes in the levels of key proteins that facilitate events involved in the underlying pathology of migraine. Paul L. Dunham, Ph.D. and his team presented their research at the American Headache Society's 52nd Annual Scientific Meeting.