Alpha band Jansen Rit

[Silvana Huertas]

Hi, 

I have been trying to generate alpha activity using the Jansen-Rit model (Figure 3, subplot 3 from up to down), but I haven't been able to get the alpha band activity with the values from the paper (1995) or the default values of TVB. I also tried changing the values of the model, and I do not see a difference on the output. 

Could you help me understand why I'm not getting the expected results? I understand that TVB made some changes to the Jansen-Rit model, however, I don't understand why I can't get the alpha band activity and why the outputs doesn't change when I vary the variables of the model (the J or the m).

I have attached my code. 

Thank you so much, 

Kind regards, 

Silvana

[WOODMAN Michael]

hi,

I noticed you are computing your spectrogram for the wrong sampling frequency in this script: you set fsamp to 1024 but you compute spectrogram on the raw time series which has a fsamp of 16khz.  Redoing this correctly generates a spectrogram with a clear fall off starting around 10 Hz, not quite the alpha bump you're after.  I suspect it's related to noise which you might have too much of: the original paper uses uniformly distributed noise which TVB doesn't support.  Unfortunately, the tails fo the normally distributed noise have a disproportianate effect.  Please try reducing noise to see if it helps generate the alpha bump.

cheers,

Marmaduke

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From: tvb-...@googlegroups.com <tvb-...@googlegroups.com> on behalf of Silvana Huertas <s.huert...@gmail.com>
Sent: Friday, October 21, 2022 6:39:06 PM
To: TVB Users
Subject: [RESEAUX SOCIAUX] [TVB] Alpha band Jansen Rit

 

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