Tissue-susceptibility matched electrodes for simultaneous magnetic resonance imaging

Motivation: How does measured fMRI signal resembles the underlying neural activity? Goal(s): Here we present a new approach of a setup, which allows simultaneous recording of neural signals during fMRI measurements at a field strength of 14.1 Tesla. Approach: The electrode design combines different materials, which alone do not have the electrical, mechanical and bio-compatible properties but together they do. Special galvanisation lowered the impedance. The susceptibility artifact was tested with a echo planar imaging. Biocompatibility was tested in in-vitro studies. Results: In-vivo electrophysiology during echo-planar imaging reached a noise level of less than 12μV at the input of the electrode after post-processing. Impact: The presented electrode is an alternative to conventional electrodes, especially at ultrahigh field strengths. Since it was possible to perform simultaneous echo-planar imaging and voltage recording, those electrodes could be used for animal experiments to gain improved functional information.