title: Effect of pulsed magnetic stimulation of the facial nerve on cerebral blood flow.
abstract: In these experiments we define an effective means of pulsed magnetic stimulation of the facial nerve for the purpose of increasing cerebral blood flow (CBF). In normal anesthetized dog and sheep, a focal magnetic field was directed toward the facial nerve within the temporal bone by placing a 6.5 cm figure-8 stimulation coil over the ear. In an initial set of experiments, CBF was measured by laser Doppler flowmetry and the cerebral vasculature was visualized by angiography. The effect of facial nerve stimulation was found to be dependent on stimulation power, frequency, and the precise positioning of the stimulation coil. Furthermore, an increase in CBF was not observed after direct electrical stimulation in the middle ear space, indicating that non-specific stimulation of the tympanic plexus, an intervening neural structure with vasoactive effects, was not responsible for the increase in CBF after pulsed magnetic stimulation. Subsequent experiments using perfusion MRI demonstrated reproducible increases in CBF throughout the forebrain that manifested bilaterally, albeit with an ipsilateral predominance. These experiments support the development of a non-invasive pulsed magnetic facial nerve stimulator that will increase CBF as a treatment of ischemic stroke.
authors.affiliation: Northern Neurosciences Inc, USA. mark.borsody@lakebiosciences.com
authors.forename: Mark K
authors.initials: MK
authors.lastname: Borsody
authors.forename: Chisa
authors.initials: C
authors.lastname: Yamada
authors.forename: Dawn
authors.initials: D
authors.lastname: Bielawski
authors.forename: Tamara
authors.initials: T
authors.lastname: Heaton
authors.forename: Bruce
authors.initials: B
authors.lastname: Lyeth
authors.forename: Andrea
authors.initials: A
authors.lastname: Garcia
authors.forename: Fernando
authors.initials: F
authors.lastname: Castro Prado
authors.forename: Joaquín
authors.initials: J
authors.lastname: Azpiroz
authors.forename: Emilio
authors.initials: E
authors.lastname: Sacristan
mesh_terms: D000818:Animals; D002560:Cerebrovascular Circulation; D004285:Dogs; D005154:Facial Nerve / Q000502:physiology*; D017078:Laser-Doppler Flowmetry; D018810:Magnetic Resonance Angiography; D012756:Sheep; D050781:Transcranial Magnetic Stimulation / Q000379:methods*
keywords: Cerebral blood flow; Facial nerve; Magnetic stimulation