Note that this reference documentation is identical to the help that is displayed in MATLAB when you type “help ft_sourceinterpolate”.
FT_SOURCEINTERPOLATE interpolates source activity or statistical maps onto the voxels or vertices of an anatomical description of the brain. Both the functional and the anatomical data can either describe a volumetric 3D regular grid, a triangulated description of the cortical sheet or an arbitrary cloud of points. The functional data in the output data will be interpolated at the locations at which the anatomical data are defined. For example, if the anatomical data was volumetric, the output data is a volume-structure, containing the resliced source and the anatomical volume that can be visualized using FT_SOURCEPLOT or written to file using FT_SOURCEWRITE. The following scenarios are possible: - Both functional data and anatomical data are defined on 3D regular grids, for example with a low-res grid for the functional data and a high-res grid for the anatomy. - The functional data is defined on a 3D regular grid of source positions and the anatomical data is defined on an irregular point cloud, which can be a 2D triangulated mesh. - The functional data is defined on an irregular point cloud, which can be a 2D triangulated mesh, and the anatomical data is defined on a 3D regular grid. - Both the functional and the anatomical data are defined on an irregular point cloud, which can be a 2D triangulated mesh. - The functional data is defined on a low resolution 2D triangulated mesh and the anatomical data is defined on a high resolution mesh, where the low-res vertices form a subset of the high-res vertices. This allows for mesh based interpolation. The algorithm currently implemented is so-called 'smudging' as it is also applied by the MNE-suite software. Use as [interp] = ft_sourceinterpolate(cfg, source, anatomy) [interp] = ft_sourceinterpolate(cfg, stat, anatomy) where source is the output of FT_SOURCEANALYSIS stat is the output of FT_SOURCESTATISTICS anatomy is the output of FT_READ_MRI or one of the FT_VOLUMExxx functions, a cortical sheet that was read with FT_READ_HEADSHAPE, or a regular 3D grid created with FT_PREPARE_SOURCEMODEL. and cfg is a structure with any of the following fields cfg.parameter = string (or cell-array) of the parameter(s) to be interpolated cfg.downsample = integer number (default = 1, i.e. no downsampling) cfg.interpmethod = string, can be 'nearest', 'linear', 'cubic', 'spline', 'sphere_avg' or 'smudge' (default = 'linear for interpolating two 3D volumes, 'nearest' for all other cases) The supported interpolation methods are 'nearest', 'linear', 'cubic' or 'spline' for interpolating two 3D volumes onto each other. For all other cases the supported interpolation methods are 'nearest', 'sphere_avg' or 'smudge'. The functional and anatomical data should be expressed in the same coordinate sytem, i.e. either both in MEG headcoordinates (NAS/LPA/RPA) or both in SPM coordinates (AC/PC). To facilitate data-handling and distributed computing you can use cfg.inputfile = ... cfg.outputfile = ... If you specify one of these (or both) the input data will be read from a *.mat file on disk and/or the output data will be written to a *.mat file. These mat files should contain only a single variable, corresponding with the input/output structure. See also FT_READ_MRI, FT_SOURCEANALYSIS, FT_SOURCESTATISTICS, FT_READ_HEADSHAPE, FT_SOURCEPLOT, FT_SOURCEWRITE