Parametric Contrast of Resting State and Task Data in Source Space

Dear colleagues,

I want to compare the 10 mins resting state data with a task data- epoched in 4 seconds, with paired t-test on PSD maps in source space. I am facing the error as in the attached below screenshot. PSD maps are computed with different frequency bands of interest. Could you please let me know how can I resolve this error or what can be other efficient ways to compare the resting state and task data in Brainstorm.

Thank you!
image

In Brainstorm, you can use the statistical tests only to compare two groups of sample files that have strictly the same structure: same time definition, same frequencies, same number of signals.
Then it runs multiple statistical tests, one per each value - the value should be available in all the files of both lists.

If you want to compare values computed in different ways, you can try to first extract the data of interest with the process Extract values, in order to obtain files with similar structures.
If you want to compare different time windows, you need to run the process Standardize > Uniform epoch time. But there is no equivalent for comparing values from different frequency bands, I don't think this is something that should be done in the first place.

Dear @Francois
Thank you for your answer. I tried to extract values and standardize the uniform epoch and signals but it didn't work. The frequency bands (theta=5-7 Hz; alpha=9-12Hz; beta=14-28 Hz, & gamma=30-50 Hz) are same across the two datasets. You are right but here we are comparing the power computed through PSD only. It might be possible to compare if the time sample becomes equivalent e.g., PSD: 7/1000ms and PSD:605/1000ms but I am not sure though.
Difference of means is not desired as well. Any other suggestion to compare the resting state data with each of the two conditions of task trials or to normalize task data with respect to resting state data in the Brainstorm?

Yes, the processing for the various files should be similar:

  • you must use the same estimator window length for all the PSD you want to compare (either 1s or 2s for all the files)
  • I recommend you use similar number of windows for all the PSD, not 7 windows for one file and 605 for the other. One file would be much noisier than the other.

@Sylvain?