Functional MRI of auditory cortex activated by multisite electrical stimulation of the cochlea

François Lazeyras, Colette Boëx, Alain Sigrist, Mohamed L. Seghier, Grégoire Cosendai, François Terrier, Marco Pelizzone

Research output: Contribution to journalArticlepeer-review

25 Scopus citations

Abstract

Electrical stimulation of the ear of deaf patients via cochlear implants offers a unique occasion to study activity of central auditory pathways with fMRI, without bias due to scanner noise. Such measurements, however, require one to control the possible interference between fMRI acquisition and the implanted electrodes. A series of measurements on a customized phantom designed to characterize the level of induced currents during MRI acquisition is presented. These experiments demonstrate that the major artifactual contribution is due to radiofrequency interaction and that safe experimental conditions can be obtained with proper shielding of the stimulation cables. The induced currents could be reduced to low levels (<50 μA for a duration <2 ms), below the acoustic perceptual threshold of cochlear implant subjects. Subsequent fMRI experiments on a patient using an Ineraid cochlear implant were conducted. Results revealed bilateral localized activation of the primary auditory cortex. Stimulation of two different intracochlear electrodes elicited activity in two neighboring, but different, regions, in agreement with the known tono-topical organization of the auditory cortex. This work paves the way for fMRI studies of a broad selection of auditory paradigms without interference from unwanted noise.

Original languageBritish English
Pages (from-to)1010-1017
Number of pages8
JournalNeuroImage
Volume17
Issue number2
DOIs
StatePublished - 2002

Keywords

  • Cochlear implant
  • Functional MRI
  • Phantom
  • Safety
  • Tonotopy

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