Dear all,
I am interested in phase-amplitude coupling (both on simulated and physiological data) and I would like to have your advice and experience in this topic.
My first question relies on the script bst_chirplet.m that generate chirplet functions. I would like to know on which basis has been fixed the values "fbw" (which I guess stand for frequency bandwidth) and "std_multiple". Those two parameters are respectively fixed to 0.15 and 6, and it appears that slightly changing these values have a great impact on PAC computation. Furthermore, I would like to know if there is any paper on the computation of chirplet functions in the frequency domain (as performed in bst_chirplet.m) (the one of Mann et al., 1995 gives the chirplet in the time domain).
My second question relies on simulated data (using the Brainstorm function process_pac_simulate.m). I simulated a signal with a coupling between 12Hz (for the phase) and 90 (for the amplitude). Looking at the comodulogram, it appears that the maximum peak at this frequency pair, but display a broad pattern extending from 10 Hz to 15 Hz. Do you have any idea why this pattern is not more "focal"?
My last question is about physiological data. I would like to apply PAC to task-based MEG data. Is the code suitable to be applied on task-based data (e.g. on trials with a window of 1.5s)? The only restriction is to have at least 10 cycles of the lowest frequency (in our case ~ 6 Hz), is that right?
Thank you for your help !
Nicolas