A flexible workflow for simulating transcranial electric stimulation in healthy and lesioned brains

PLoS One. 2020 May 14;15(5):e0228119. doi: 10.1371/journal.pone.0228119. eCollection 2020.

Abstract

Simulating transcranial electric stimulation is actively researched as knowledge about the distribution of the electrical field is decisive for understanding the variability in the elicited stimulation effect. Several software pipelines comprehensively solve this task in an automated manner for standard use-cases. However, simulations for non-standard applications such as uncommon electrode shapes or the creation of head models from non-optimized T1-weighted imaging data and the inclusion of irregular structures are more difficult to accomplish. We address these limitations and suggest a comprehensive workflow to simulate transcranial electric stimulation based on open-source tools. The workflow covers the head model creation from MRI data, the electrode modeling, the modeling of anisotropic conductivity behavior of the white matter, the numerical simulation and visualization. Skin, skull, air cavities, cerebrospinal fluid, white matter, and gray matter are segmented semi-automatically from T1-weighted MR images. Electrodes of arbitrary number and shape can be modeled. The meshing of the head model is implemented in a way to preserve the feature edges of the electrodes and is free of topological restrictions of the considered structures of the head model. White matter anisotropy can be computed from diffusion-tensor imaging data. Our solver application was verified analytically and by contrasting the tDCS simulation results with that of other simulation pipelines (SimNIBS 3.0, ROAST 3.0). An agreement in both cases underlines the validity of our workflow. Our suggested solutions facilitate investigations of irregular structures in patients (e.g. lesions, implants) or new electrode types. For a coupled use of the described workflow, we provide documentation and disclose the full source code of the developed tools.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Algorithms
  • Anisotropy
  • Brain / diagnostic imaging
  • Brain / physiology*
  • Brain / radiation effects
  • Central Nervous System / diagnostic imaging
  • Central Nervous System / physiology*
  • Central Nervous System / radiation effects
  • Diffusion Tensor Imaging
  • Gray Matter / diagnostic imaging
  • Gray Matter / radiation effects
  • Head / diagnostic imaging
  • Head / physiology*
  • Head / radiation effects
  • Humans
  • Image Processing, Computer-Assisted
  • Magnetic Resonance Imaging
  • Models, Theoretical
  • Transcranial Direct Current Stimulation*
  • White Matter / diagnostic imaging
  • White Matter / radiation effects
  • Workflow

Grant support

Benjamin Kalloch was funded by FAZIT-STIFTUNG and the International Max Planck Research School on the Neuroscience of Communication (IMPRS NeuroCom).