Removing Non-linear Trends

Though a script exists to use FreeSurfer's tools to remove linear trends as it extracts the time course data, non-linear trends may lurk in the data.

This might be problematic for some analyses. Fortunately, nonlinear trends can be removed from the data once it's been loaded into MATLAB, before any further processing (e.g., normalizing, etc.) is done to it.

Assume you have a cell array of matrices, M, which was generated by the loadFSTS function.