Roi wts: Difference between revisions
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==Description== |
==Description== |
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The purpose of roi_wts is to leverage the orientation information from the FreeSurfer parcellation of the brain when solving for the beamformer weights. Normally, in a SAM analysis, the orientations calculated by solving the linear eigensystem equations and choosing the vector that gives the largest S/N. In roi_wts, the cortical normal vector is used instead. It is of paramount importance that the registration of the MEG and MRI are accurate. Thus, this program should only be run if you have already run sam_coreg. Obviously, one must have run FreeSurfer before running this program. |
The purpose of roi_wts is to leverage the orientation information from the FreeSurfer parcellation of the brain when solving for the beamformer weights. Normally, in a SAM analysis, the orientations calculated by solving the linear eigensystem equations and choosing the vector that gives the largest S/N. In roi_wts, the cortical normal vector is used instead. It is of paramount importance that the registration of the MEG and MRI are accurate. Thus, this program should only be run if you have already run sam_coreg. Obviously, one must have run FreeSurfer before running this program. This program also makes use of whatever parcellation that you have requested FreeSurfer use to annotate your surface. |
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roi_wts uses the Nolte (realistic) head model, and will ignore other specifications of the Model parameter. By default, a 20th order harmonic expansion of the hull is used. |
roi_wts uses the Nolte (realistic) head model, and will ignore other specifications of the Model parameter. By default, a 20th order harmonic expansion of the hull is used. |
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Required Parameters (in the .param file or on the command line): |
Required Parameters (in the .param file or on the command line): |
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CovBand: bandpass for covariance matrix calculation |
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Transform: Must be TRUE |
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Atlas: specifies the file |
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Optional Parameters: |
Optional Parameters: |
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Revision as of 10:18, 6 March 2019
Return to Source Localization - SAM
Description
The purpose of roi_wts is to leverage the orientation information from the FreeSurfer parcellation of the brain when solving for the beamformer weights. Normally, in a SAM analysis, the orientations calculated by solving the linear eigensystem equations and choosing the vector that gives the largest S/N. In roi_wts, the cortical normal vector is used instead. It is of paramount importance that the registration of the MEG and MRI are accurate. Thus, this program should only be run if you have already run sam_coreg. Obviously, one must have run FreeSurfer before running this program. This program also makes use of whatever parcellation that you have requested FreeSurfer use to annotate your surface.
roi_wts uses the Nolte (realistic) head model, and will ignore other specifications of the Model parameter. By default, a 20th order harmonic expansion of the hull is used.
roi_wts -r <dataset_name> -m <parameter_file_name> [options]
The -r flag designates the dataset name (with or without the .ds suffix), and -m designates the parameter file name.
Other options:
-v Verbose mode, without this flag sam_wts works silently except for error messages -h Show help
Required Parameters (in the .param file or on the command line):
CovBand: bandpass for covariance matrix calculation Transform: Must be TRUE Atlas: specifies the file
Optional Parameters:
MRIDirectory: Specify where to locate the necessary MRI files PrefixLength: Specify characters used for identifying MRI and headmodel files.