In this section we will apply RAP-MUSIC reconstruction and visualize the estimated MEG dipolar sources on the MRI volume. For details on the RAP-MUSIC method see [1] and the other publications by the USC Neuroimaging Research Group.
- Make sure that your current Database and Data Folder are selected correctly in Data Manager window (BSTDemo and somDemo_av.ds/BrainStorm respectively). If it is correct, leave everything as is in Data Viewer to limit the reconstruction in the 20-60ms time range (where the stimulus response is apparent in the time courses). Otherwise, select the correct dataset in Data Manager and load this data (Hint: To load the data see Tutorial for Data Visualization ) and select the time range as 20-60ms.
- In the Analysis section select RAP-MUSIC in the drop down menu. The Parametric Estimation Data Selector window will open.
- Change the Rank to 4 and leave all other options default. You can see the BrainStorm documentation for a complete description of the available options in this window.
- Press Done, the Parameters RAP-MUSIC window should open.
- Change the Correlation Threshold to 0.90. The higher this value, the more accurate the MEG measurements subspace matches the model subspace. However, no sources will be found if the value is set too high.
- Press Execute to run the RAP-MUSIC algorithm. A few seconds later you will see the MRI Tool, Topography
and the TimeSeries pop-up windows. Observe the identified sources in the MRI Tool, and corresponding timeseries in the TimeSeries pop-up window.
The results are stored in the C:\BSTDemoData\Study\somDemo_av.ds\BrainStorm\ folder in the files somDemo_av_results_Trial1_(time created).mat.
| [1] |
S. Baillet, J.C. Mosher, R.M. Leahy, "Electromagnetic Brain Mapping", (invited article), IEEE Signal Processing Magazine, 18(6): 14-30, Nov 2001. pdf |
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