Change sampling frequency of a dataset


I created a while ago a dataset with 250 subjects. Now, I am suspicious that the sampling frequency that I used when importing it to Brainstorm is wrong. How can I check the sampling frequency that I selected for those registers? Besides, can I modify the sampling frequency of the subjects in that database without removing and re-importing them?

Thank you very muvh in advance!

You load any imported epoch into your Matlab workspace (e.g. right-click on the file > File > Export to Matlab > DataMat), and execute:

>> sfreq = 1 ./ (DataMat.Time(2)-DataMat.Time(1))
sfreq =


>> sfreq = mean(1 ./ diff(DataMat.Time))
sfreq =

You can modify this manually, at least on one file, by updating the Time field.

Then you can select this file in Process1, followed by all the other trials in your database explorer, and use the process "Standardize > Uniform epoch time".

Thank you very much, as always it was what I needed :smiley: