title: Neuronal responses to magnetic stimulation reveal cortical reactivity and connectivity.
abstract: Motor and visual cortices of normal volunteers were activated by transcranial magnetic stimulation. The electrical brain activity resulting from the brief electromagnetic pulse was recorded with high-resolution electroencephalography (HR-EEG) and located using inversion algorithms. The stimulation of the left sensorimotor hand area elicited an immediate response at the stimulated site. The activation had spread to adjacent ipsilateral motor areas within 5-10 ms and to homologous regions in the opposite hemisphere within 20 ms. Similar activation patterns were generated by magnetic stimulation of the visual cortex. This new non-invasive method provides direct information about cortical reactivity and area-to-area neuronal connections.
authors.affiliation: BioMag Laboratory, Medical Engineering Centre, Helsinki University Central Hospital, Finland.
authors.forename: R J
authors.initials: RJ
authors.lastname: Ilmoniemi
authors.forename: J
authors.initials: J
authors.lastname: Virtanen
authors.forename: J
authors.initials: J
authors.lastname: Ruohonen
authors.forename: J
authors.initials: J
authors.lastname: Karhu
authors.forename: H J
authors.initials: HJ
authors.lastname: Aronen
authors.forename: R
authors.initials: R
authors.lastname: Näätänen
authors.forename: T
authors.initials: T
authors.lastname: Katila
mesh_terms: D000328:Adult; D000465:Algorithms; D001931:Brain Mapping; D004569:Electroencephalography / Q000528:radiation effects*; D005071:Evoked Potentials; D005260:Female; D007839:Functional Laterality; D006225:Hand / Q000294:innervation; D006801:Humans; D008280:Magnetics; D008297:Male; D009044:Motor Cortex / Q000502:physiology* / Q000528:radiation effects; D011930:Reaction Time; D014793:Visual Cortex / Q000502:physiology* / Q000528:radiation effects