Brain fluid dynamics key to migraine mysteries, new therapies

 New research describes for the first time how a spreading wave of disruption and the flow of fluid in the brain triggers headaches, detailing the connection between the neurological symptoms associated with aura and the migraine that follows. The study also identifies new proteins that could be responsible for headaches and may serve as foundation for new migraine drugs.

"In this study, we describe the interaction between the central and peripheral nervous system brought about by increased concentrations of proteins released in the brain during an episode of spreading depolarization, a phenomenon responsible for the aura associated with migraines," said Maiken Nedergaard, MD, DMSc, co-director of the University of Rochester Center for Translational Neuromedicine and lead author of the new study, which appears in the journal Science. "These findings provide us with a host of new targets to suppress sensory nerve activation to prevent and treat migraines and strengthen existing therapies."t is estimated that one out of 10 people experience migraines and in about a quarter of these cases the headache is preceded by an aura, a sensory disturbance that can includes light flashes, blind spots, double vision, and tingling sensations or limb numbness. These symptoms typically appear five to 60 minutes prior to the headache.

The cause of the aura is a phenomenon called cortical spreading depression, a temporary depolarization of neurons and other cells caused by diffusion of glutamate and potassium that radiates like a wave across the brain, reducing oxygen levels and impairing blood flow. Most frequently, the depolarization event is located in the visual processing center of the brain cortex, hence the visual symptoms that first herald a coming headache.

While migraines auras arise in the brain, the organ itself cannot sense pain. These signals must instead be transmitted from the central nervous system -- the brain and spinal cord -- to the peripheral nervous system, the communication network that transmits information between brain with the rest of the body and includes sensory nerves responsible for sending information such as touch and pain. The process of communication between the brain and peripheral sensory nerves in migraines has largely remained a mystery.

Fluid Dynamics Models Shed Light on Migraine Pain Origins

Nedergaard and her colleagues at the University of Rochester and the University of Copenhagen are pioneers in understanding the flow of fluids in the brain. In 2012, her lab was the first to describe the glymphatic system, which uses cerebrospinal fluid (CSF) to wash away toxic proteins in the brain. In partnership with experts in fluid dynamics, the team has built detailed models of how the CSF moves in the brain and its role in transporting proteins, neurotransmitters, and other chemicals.

Source: ScienceDaily