make_inverse_operator(info, forward, noise_cov, loose='auto', depth=0.8, fixed='auto', rank=None, use_cps=True, verbose=None)¶
Assemble inverse operator.
The measurement info to specify the channels to include. Bad channels in info[‘bads’] are not used.
- noise_covinstance of
The noise covariance matrix.
floatin [0, 1] | ‘auto’
Value that weights the source variances of the dipole components that are parallel (tangential) to the cortical surface. If loose is 0 then the solution is computed with fixed orientation, and fixed must be True or “auto”. If loose is 1, it corresponds to free orientations. The default value (‘auto’) is set to 0.2 for surface-oriented source space and set to 1.0 for volumetric, discrete, or mixed source spaces, unless
fixed is Truein which case the value 0. is used.
How to weight (or normalize) the forward using a depth prior. If float (default 0.8), it acts as the depth weighting exponent (
exp) to use, which must be between 0 and 1. None is equivalent to 0, meaning no depth weighting is performed. It can also be a dict containing keyword arguments to pass to
mne.forward.compute_depth_prior()(see docstring for details and defaults). This is effectively ignored when
Changed in version 0.20: Depth bias ignored for
- fixedbool | ‘auto’
Use fixed source orientations normal to the cortical mantle. If True, the loose parameter must be “auto” or 0. If ‘auto’, the loose value is used.
dict| ‘info’ | ‘full’
This controls the rank computation that can be read from the measurement info or estimated from the data. See
mne.compute_rank()for details.The default is None.
Whether to use cortical patch statistics to define normal orientations for surfaces (default True).
- invinstance of
- invinstance of
For different sets of options (loose, depth, fixed) to work, the forward operator must have been loaded using a certain configuration (i.e., with force_fixed and surf_ori set appropriately). For example, given the desired inverse type (with representative choices of loose = 0.2 and depth = 0.8 shown in the table in various places, as these are the defaults for those parameters):
Forward parameters allowed
surf_oriLoose constraint,Depth weighted
TrueFree orientation,Depth weighted
True | FalseFixed constraint,Depth weighted
Also note that, if the source space (as stored in the forward solution) has patch statistics computed, these are used to improve the depth weighting. Thus slightly different results are to be expected with and without this information.