You can change the p-value threshold interactively with the Stat tab, or set permanently with the process Test > Apply statistic threshold.
The t-statistic are the values you see in the colormap. You can get more precise graphs showing the value over time by creating scouts and displaying their time series.
- https://neuroimage.usc.edu/brainstorm/Tutorials/Statistics#Example_4:_Parametric_test_on_sources
- https://neuroimage.usc.edu/brainstorm/Tutorials/Scouts
For all the other measures, you need to do it manually in Matlab, from pmap and tmap fields:
- https://neuroimage.usc.edu/brainstorm/Tutorials/Statistics#On_the_hard_drive
- https://neuroimage.usc.edu/brainstorm/Tutorials/Scripting#Custom_processing
I want to validate the same at the source level and get the exact sources of such activity. How do I go about it?
Use scouts time series instead of sensors, and repeat exactly the same analysis.
I want to define one scout in one hemisphere
If you find a couple of ROIs in one of the atlases that corresponds to what you want: use these ones (not too large, otherwise the effect of interest might get lost in the averaging of all the signals within the scouts). Otherwise, draw them on default anatomy, project them on the individual brains, and adjust for each subject individually if there are points that are not projected correctly.
Do I take the constrained sources of all the trials and then run coherence process?
If you are only interested strictly on the coherence between two ROIs: you can use the tab Process2 with the same list of source files on the left and on the right (all the individual trials for one subject and one condition, constrained sources), and use the process Coherence AxB, select the left ROI for FilesA, the right ROI for FilesB (or vice versa). Repeat (or script) for the conditions, and all the subjects.
Then run your paired non-parametric stat on the resulting files.
At source level, how do I specify the electrode (surrounding which I'll define my scout) for 1*N coherence?
If you want to compute the coherence between one electrode and multiple scouts: use Process2 / Coherence AxB as well, selecting the recordings on the left, and the sources on the right. But I'm not sure I understand why you'd want to do this in this context.