PZ node is not active

[lala z]

Hello, I'm trying to use BVEP. I use the brain imaging data of our own epilepsy patients and generate the structural connection matrix by running tvb- recon. Then I try to use the structural connection matrix for forward simulation. I run two codes, BVEP/ TVB / forwardsimulation_ VEPmodel_ patient1. Ipynb and BVEP / TVB / forwarssimulation_ VEPmodel_ SEEG_ patient1. Ipynb, as in the code, set nodes 6 and 34 as EZ, 5, 11 and 27 as PZ, and the rest as Hz. However, I found that the result only shows that EZ node is active, and no PZ node is responding. What is the reason? Is it related to the patient's connection matrix? Is this a normal phenomenon?

[meysam....@gmail.com]

Thanks for the question.

The propagation needs a high coupling value and dramatically depends on SC and excitability values.

One solution is to increase coupling K, or increase the excitability value for these nodes closer to critical value -2.05.

A simpler way is to increase coupling between EZ and PZ, according to the clinical hypothesis.

Best,

Meysam

[lala z]

Hello, I adjusted the node of the propagation area to be close to the critical value -2.05, but now I realize that I can only have obvious effect when I adjust it to -2.05, so I intend to adjust the K value, but I don't know how to adjust K. is this k value a parameter in TVB, or do I directly operate the weight value of the connection matrix? As you said, how to adjust the coupling value of Ez and PZ?

[lala z]

I found several coupling parameters in the TVB tutorial, they are  fast variable (Kvf) , spike-and-wave events (Kf) ,and  slow permittive coupling (Ks)    but I'm not sure whether they are the global coupling coefficient K, so how can I adjust them?

[WOODMAN Michael]

hi

These parameters are usually tuned independently depending on your hypothesis of the mechanism of seizure propagation.  Please see the papers associated with the Epileptor model by Proix et al. 

cheers,

Marmaduke

---

From: 'lala z' via TVB Users <tvb-...@googlegroups.com>
Sent: Thursday, May 5, 2022 2:08:07 PM
To: TVB Users
Subject: [TVB] Re: PZ node is not active

 

--
You received this message because you are subscribed to the Google Groups "TVB Users" group.
To unsubscribe from this group and stop receiving emails from it, send an email to tvb-users+...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/tvb-users/59d9bd92-2ca1-4821-be2d-5a9f70c92cbcn%40googlegroups.com.