Imported MEG/EEG files to combine/overlay together and then do Morlet wavelets and Hilbert transform

Discussions
1

Hi, there,

I’ve been doing it for single imported EEG files in .edf format recorded from mouse EEG.
It’s possible that I missed this in tutorials,

Is there a way to combine all those files into one file in brainstorm (overlay format) and then do the Morlet wavelets and Hilbert transform?

Thanks.

2

Hello,
I’m not sure I understand what you mean with “overlay format”.
Can you be more explicit about the type of output or figure you are expecting to get?
Thanks
Francois

3

I’ve imported multiple parts of the recorded file (over several days), each part presumably contains oscillation of interest and 20 minutes in length. I want to combine all those files (20), into one file, without changing the data (so all the traces will be visible at the same time).

Then I want to do Morlet wavelets and Hilbert transform on them.

So the output will show whether specific frequencies are overrepresented in such combined file.

Thanks for trying to help:)

4

If you want to concatenate all the files (assemble them one after the other), you can select them all in Process1 and use the process “Standardize > Concatenate time”.
There are many other options available: for instance you could extract only one channel of recordings for all the segments of 20min, and put all the signals in the same file. You can do such things with the process “Extract > Extract values”.

If the segments are 20 min long each, it might be difficult to process the concatenatenated file at once. You could process the time-frequency decomposition of each segmented separately.

Does it help?
I’m not sure I understand what you have in mind. If you need additional options, please describe in details what you expect, maybe illustrated with a screen capture. And explain what you expect to get from the results you are trying to compute with Brainstorm.

5

The concatenate option is not what I need, it’s in your tutorials and I tried it before.

I don’t need those files organized in a sequential order in one file I need those files to be on top of each other in one file and not displayed separately as coming from different leads, but just overlay each other. So it’s like an average without actual average calculation.

If I could Illustrate it with brainstorm using screen capture I wouldn’t be asking for help doing that.

It’s like recording multiple trials from the same lead in EEG, that consequently overlay each other (without deleting the previous trial). So the time (x axis) would be the same for all those files and the amplitude (y axis) will contain all the recordings from all those files.

Maybe it’s more like having multiple channels with the same time scale (x axis).

6

Then use “Extract > Extract values”, enter the name of one sensor, and select “Concatenate signals”.
This will save all the extracted signals in one single file, and you’ll be able to display all the trials in the same figure.

7

Thanks for the help.

That worked. I couldn’t see all the traces, but I guess it’s a graphic representation issue, if i display as image it shows all the combined single signals.