• SimNIBS is a software for the Simulation of Non-invasive Brain Stimulation. It allows for realistic calculations of the electric field induced by transcranial magnetic stimulation (TMS). Basic support for transcranial direct current stimulation (tDCS) is currently tested and will be added within the next few months.
• SimNIBS consists of two main parts:
  • A command line script is used for the automatic generation of tetrahedral volume meshes of the head from MR images.
  • These volume meshes are then used in the electric field calculations based on finite elements. A range of MATLAB functions (The Mathworks, MA, USA) is provided to support the latter step.
• The Installation section describes how to download and set up SimNIBS under Ubuntu 10.04 LTS 64-bit.
• The Documentation section guides you through SimNIBS in a step-by-step fashion based on an example data set.
• Note: SimNIBS is a research tool. Clinical usage is not supported or advised. In particular, SimNIBS was not tested to give accurate results in the presence of pathological conditions

SimNIBS was created at the Max-Planck Institute for Biological Cybernetics (Tübingen, Germany) by Mirko Windhoff, Alex Opitz and Axel Thielscher. SimNIBS is distributed under the GNU GPL v2. When you publish results based on SimNIBS or parts of it, please cite:

• Windhoff, M., Opitz, A. and Thielscher, A. (2011), Electric field calculations in brain stimulation based on finite elements: An optimized processing pipeline for the generation and usage of accurate individual head models. Human Brain Mapping

SimNIBS integrates free software for neuroimaging, computer graphics and FEM calculations into one coherent pipeline:

• FreeSurfer, from the Athinoula A. Martinos Center for Biomedical Imaging
• FSL, from the FMRIB Center (Oxford University)
• MeshFix, by Marco Attene
• Gmsh, by Christophe Geuzaine and Jean-François Remacle
• GetFEM++, by Yves Renard and Julien Pommier.

We are particularly thankful for the support of Yves Renard when implementing the field equations in GetFEM++. Many thanks also go to Marco Attene for releasing MeshFix as open source and for his support when extending it.