RT Journal Article SR Electronic T1 iELVis: An open source MATLAB toolbox for localizing and visualizing human intracranial electrode data JF bioRxiv FD Cold Spring Harbor Laboratory SP 069179 DO 10.1101/069179 A1 David M. Groppe A1 Stephan Bickel A1 Andrew R. Dykstra A1 Xiuyuan Wang A1 Pierre Mégevand A1 Manuel R. Mercier A1 Fred A. Lado A1 Ashesh D. Mehta A1 Christopher J. Honey YR 2016 UL http://biorxiv.org/content/early/2016/11/30/069179.abstract AB Background Intracranial electrical recordings (iEEG) and brain stimulation (iEBS) are invaluable human neuroscience methodologies. However, the value of such data is often unrealized as many laboratories lack tools for localizing electrodes relative to anatomy. To remedy this, we have developed a MATLAB toolbox for intracranial electrode localization and visualization, iELVis.New Method iELVis uses existing tools (BioImage Suite, FSL, and FreeSurfer) for preimplant magnetic resonance imaging (MRI) segmentation, neuroimaging coregistration, and manual identification of electrodes in postimplant neuroimaging.Subsequently, iELVis implements methods for correcting electrode locations for postimplant brain shift with millimeter-scale accuracy and provides interactive visualization on 3D surfaces or in 2D slices with optional functional neuroimaging overlays. iELVis also localizes electrodes relative to FreeSurfer-based atlases and can combine data across subjects via the FreeSurfer average brain.Results It takes 30-60 minutes of user time and 12-24 hours of computer time to localize and visualize electrodes from one brain. We demonstrate iELVis’s functionality by showing that three methods for mapping primary hand somatosensory cortex (iEEG, iEBS, and functional MRI) provide highly concordant results.Comparison with Existing Methods iELVis is the first public software for electrode localization that corrects for brain shift, maps electrodes to an average brain, and supports neuroimaging overlays. Moreover, its interactive visualizations are powerful and its tutorial material is extensive.Conclusions iELVis promises to speed the progress and enhance the robustness of intracranial electrode research. The software and extensive tutorial materials are freely available as part of the EpiSurg software project: https://github.com/episurg/episurg