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Visiting Colloquium Presenters- 2015

 

David Zee, M.D.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.

 

Linda Spear, Ph.D.December 3rd 2015


Linda Spear, Ph.D.

Distinguished Professor of Psychology
SUNY - Binghamton 


Contributors to and Consequences of Adolescent Alcohol Exposure: Studies in a Rodent Model

Adolescents ingest more alcohol per occasion than do adults. This age effect is evident not only in human adolescents but also in laboratory animals undergoing this developmental transition, suggesting that such intakes may be partly biologically based. Work using rodent models has revealed that adolescents display an attenuated sensitivity to many alcohol effects likely serving as cues to moderate drinking, but enhanced sensitivity to ethanol-induced social stimulation and rewarding effects. This developmental blending of increased and decreased EtOH sensitivities may promote relatively high levels of alcohol intake, especially among at-risk adolescents, potentially leading to lasting adverse consequences. Indeed, recent pre-clinical studies have revealed notable enduring neural and behavioral consequences of adolescent EtOH exposure, including persistence of some adolescent phenotypes into adulthood.