Visiting Colloquium Professors - 2015
March 26th 2015
David Zee, M.D.
Professor of Department of Neurology
Johns Hopkins School of Medicine
The Surprising Effects of the Magnetic Fields of MRI Machines on the Labyrinth and Brain
Vertigo in and around magnetic resonance imaging (MRI) machines has been noted for years but was unexplained. We found that all healthy human subjects develop a robust nystagmus while simply lying in the static magnetic field of an MRI machine. Patients lacking labyrinthine function did not. We show that magnetic vestibular stimulation (MVS) derives from a Lorentz force resulting from interaction between the magnetic field and naturally occurring ionic currents in the labyrinthine endolymph fluid. This force pushes on the semicircular canal cupula, leading to nystagmus. We will use this force to study behavior in normal humans, patients with vestibular lesions, zebra fish and mice. We discuss implications for functional and resting state MRI.