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MNECorticalMap

Namespace: MNELIB  ·  Library: MNE Library

#include <mne/mne_cortical_map.h>

class MNELIB::MNECorticalMap

Builds the resolution matrix K G that maps source activity to its estimate.

Resolution matrix of an inverse operator

src/examples/ex_inv_api/main.cpp
// The same resolution matrix from a prepared inverse; the forward is rotated to the inverse's surface basis
MNEInverseOperator prepared = inverse.prepare_inverse_operator(evoked.nave, lambda2, false, false);
MatrixXd surfaceKernel;
SparseMatrix<double> noNormals;
QList<VectorXi> kernelVertices;
prepared.assemble_kernel(FsLabel(), "MNE", false, surfaceKernel, noNormals, kernelVertices);
prepared.getKernel() = surfaceKernel;
const MatrixXd corticalMap = MNECorticalMap::makeCorticalMap(fwd, prepared, evoked.info);

Public Methods​

MNECorticalMap()​

Static Methods​

makeCorticalMap(fwd, inv, info)​

Create the resolution matrix M = K G that maps source activity to its estimate.

K is the inverse operator kernel; G holds the rows of the forward gain for the kernel's channels, matched by name (mne-python make_inverse_resolution_matrix).

Parameters:

  • fwd : const MNEForwardSolution & The forward solution containing the gain matrix.

  • inv : const MNEInverseOperator & The inverse operator (must have been prepared / have a kernel).

  • info : const FiffInfo & The measurement info for channel selection.

Returns:

  • Eigen::MatrixXd — The cortical mapping matrix (nSources x nSources).

Example​

Used in examples​

ex_inv_api​

Inverse library: minimum-norm estimates, resolution matrices, label time courses, sparse solvers.

src/examples/ex_inv_api/main.cpp, line 157
QList<VectorXi> kernelVertices;
prepared.assemble_kernel(FsLabel(), "MNE", false, surfaceKernel, noNormals, kernelVertices);
prepared.getKernel() = surfaceKernel;
const MatrixXd corticalMap = MNECorticalMap::makeCorticalMap(fwd, prepared, evoked.info);
// mne K (Cartesian) times the Cartesian gain, the same product in one basis: trace 26.1330, Frobenius norm 6.13353
ok &= expect(corticalMap.rows() == 210 && corticalMap.cols() == 210 && near(corticalMap.trace(), 26.133038866971994, 1e-4) && near(corticalMap.norm(), 6.13352636100184, 1e-4),
             "MNECorticalMap: K G in the inverse's surface basis matches mne");

Authors of this file​