mne_volume_source_space
Overview
mne_volume_source_space creates a volumetric source space by placing sources on a regular 3D grid inside the brain volume. Unlike surface-based source spaces that are confined to the cortical surface, volume source spaces can represent sources throughout the brain, including subcortical structures.
This is a C++ port of the original MNE-C tool by Matti Hämäläinen.
Usage
mne_volume_source_space [options]
Options
| Option | Description |
|---|---|
--bem <file> | BEM FIFF file (inner skull surface used as boundary) |
--grid <mm> | Grid spacing in mm (default: 7.0) |
--exclude <mm> | Exclude points closer to center of mass than this (default: 0) |
--mindist <mm> | Minimum distance from surface in mm (default: 5.0) |
--out <file> | Output source space FIFF file |
--help | Print help |
--version | Print version |
Description
The tool generates a regular 3D grid of source points inside the brain volume, bounded by the inner skull surface from a BEM model. Points too close to the inner skull surface (controlled by --mindist) are excluded to avoid numerical issues in forward computation.
The grid spacing controls the density of the source space. Smaller values produce more source points but require more computation time for the forward solution and inverse operator.
Workflow Context
Volume source spaces are used when subcortical sources are of interest or when surface-based source spaces are not appropriate:
- Create BEM model →
mne_watershed_bem/mne_setup_forward_model - Create volume source space →
mne_volume_source_space - Compute forward solution →
mne_forward_solution
Example
# Create a volume source space with 5 mm grid spacing
mne_volume_source_space --bem sam-inner_skull-bem.fif --grid 5.0 --out sam-vol-src.fif
# Increase minimum distance from skull surface
mne_volume_source_space --bem sam-inner_skull-bem.fif --grid 7.0 --mindist 10.0 --out sam-vol-src.fif