[FieldTrip] Calculating half peak values after applying ft_globalmeanfield

[Fairs, Amie]

Dear FieldTrip community,

Apologies for what is likely a simple question. I have some EEG data and have calculated the global field power by using ft_globalmeanfield. I would now like to detect the peaks in the signal, and specifically to work out the time windows around these peaks using a half peak measurement - thus, the time windows would span from the half peak value before the peak to the half peak value after the peak.

I have done this subjectively by eyeballing the data in a plot, highlighting the peak and literally just looking at where the halfway point from the trough to the peak is (and then reading that time value off of the x axis) but this is not the right way to do such a thing :) Does anyone know if there is a FieldTrip function that can take my GFP values, find the peaks, and then calculate the windows around the peaks in a principled manner (ideally using a half peak cut off)? I have searched the FT website, looked through the reference list (and the index) for a function, and googled, but can't find a way that is already implemented. My matlab coding skills are not wonderful, which is why I would prefer a function already written (if available).

[For more context, the reason I am doing this is to find the time windows surrounded the peaks in GFP throughout the trial, and then to test effects of my variables of interest within those time windows. So this is to find time windows for later analysis.]

Best,

Amie

-----------------------------------------------------
Amie Fairs

** I am mostly using another email address for my new position, so please add that to your address book. This email address will eventually expire. The new address:
Amie.fairs at univ-amu.fr<mailto:Amie.fairs at univ-amu.fr>
**

PhD candidate
International Max Planck Research School for Language Sciences
Max Planck Institute for Psycholinguistics
PO Box 310 | 6500 AH Nijmegen | The Netherlands
Email: amie.fairs at mpi.nl<mailto:amie.fairs at mpi.nl> | Phone: +31(0)243521381

Post-doctorant
Aix-Marseille Université
Laboratoire Parole et Langage (LPL) | CNRS UMR 7309 | 5 Avenue Pasteur | 13100 Aix-en-Provence
Email : amie.fairs at univ-amu.fr<mailto:amie.fairs at univ-amu.fr>

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.science.ru.nl/pipermail/fieldtrip/attachments/20190708/7a4bc0ef/attachment-0001.html>
-------------- next part --------------
_______________________________________________
fieldtrip mailing list
https://mailman.science.ru.nl/mailman/listinfo/fieldtrip
https://doi.org/10.1371/journal.pcbi.1002202