Seed PLS Analysis

We can use correlation between datamat value from a seed voxel and entire brain datamat to run Regular Behav PLS analysis, and we call this Seed PLS analysis.

Step-by-Step Procedures

1. Open a PET, E.R.fMRI or Blocked fMRI result file to the result window, and search for seed voxels.
2. Write down their XYZmm locations (must be voxel location with unit in millimeter, not absolute voxel location). In order to avoid out of memory problem, please choose only a few positions. For E.R.fMRI, don't worry about lags, since all lags in temporal window will be extracted.
3. Click Multiple Voxel Extraction under Windows menu to extract multiple voxels for above locations, and it will generate two kinds of files below. However, we only use Format A file here, which includes all subjects in all groups:

• Format A: PREFIX_MODULEvoxeldata.txt (only 1 file) (This one includes all subjects in all groups)

• Format B: PREFIX_MODULE_grp_[subj]_voxeldata.txt (Each of these files will correspond to each sessiondata file)

4. Check the extracted values. If it is all the same for certain column, please remove the entire column. For example, for E.R.fMRI, the baseline lag (lag0) usually contains all 0, and it should be removed.
5. Start Run PLS Analysis window. Add the same datamats and select the same conditions as you did to create the above result file.
6. Choose Regular Behav PLS option. Click Load behavior data button, and load the behavior data in format A (including all subjects in all groups). If there is any column (specified by Behavior Name) containing the same Behavior Data value across all rows in the edit window, that column should be removed.
7. Enter the number of Permutation / Bootstrap (optional), and click Run to run Seed PLS Analysis.