[Eeglablist] Bilateral dipoles

[Salim Al-wasity]

Dear Mr. MakotoPlease find the attached pictures which illustrate the use of one dipole, two dipoles (with symmetry constrain ON) and two dipoles (with symmetry constrain OFF). My question is if the unsymmetrical dipoles not recommended, What can I do with such scalp map to get the best dipoles?
SincerelySalim
https://drive.google.com/file/d/0B-waDFAaEHcuRmR0U19JN1VSMG8/view?usp=sharing
https://drive.google.com/file/d/0B-waDFAaEHcudlpkc3NDaUtueVU/view?usp=sharing
1 dipole.JPG

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without symmetry.JPG

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     On Thursday, 26 March 2015, 18:01, Makoto Miyakoshi <mmiyakoshi at ucsd.edu> wrote:
   

 No, that is not recommended. If you put more dipoles, residual variances become always smaller, which is meaningless. You have no reason to justify the two dipoles in terms of ICA; ICA usually gives you dipolar scalp topos for true EEG sources...
Makoto
On Sat, Mar 21, 2015 at 4:39 AM, Salim Al-wasity <salim_alwasity at yahoo.com> wrote:

DearsI ran the 'fine_fit' with 'symmetry constrain for dipole' is OFF. I did that to get lower RV value. 


     On Thursday, 19 March 2015, 17:48, Makoto Miyakoshi <mmiyakoshi at ucsd.edu> wrote:
   

 Dear Salim,
Well, I'm concerned with the two dipole fit results. They don't seem symmetrical. How did you obtain the current positions?
Makoto
On Thu, Mar 5, 2015 at 1:28 AM, Salim Al-wasity <salim_alwasity at yahoo.com> wrote:

Dear Mr. MakotoThanks for your reply. I attached a picture of bilateral dipoles obtained by (Locate Dipoles using DIPFIT2> Plot component dipoles) and it shows only only coordinate. However (Locate Dipoles using DIPFIT2> Fine fit) shows two coordinates. Which coordinates are the correct one?
SincerelySalim
dipoles.JPG

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 fine fit.JPG
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     On Wednesday, 4 March 2015, 15:50, Salim Al-wasity <salim_alwasity at yahoo.com> wrote:
   

 Dear Mr. MakotoThanks for your reply. I attached a picture of bilateral dipoles obtained by (Locate Dipoles using DIPFIT2> Plot component dipoles) and it shows only only coordinate. However (Locate Dipoles using DIPFIT2> Fine fit) shows two coordinates. Which coordinates are the correct one?
SincerelySalim 

     On Tuesday, 3 March 2015, 2:03, Makoto Miyakoshi <mmiyakoshi at ucsd.edu> wrote:
   

 Dear Salim and Arno (cc Caterina)
Sorry for the slow response.
> Therefore I used bilateral dipoles to reduce the RV.

Use bilateral dipole only when you see clear bilateral scalp topography!
> 1- In (plot component dipoles) options, it gives me only one coordination ever if I have two dipoles. How can I know where these two dipoles are?
Really? That sounds weird to me. You should close the fine fit window by pressing 'ok' and not 'x' to update the data.
>2- Using a PCA clustering approach, I might find one cluster located at the right hemisphere but it has some dipoles at the left side (bilateral dipoles), Is this cluster correct?
Yes, that should be correct. To be honest I don't know how STUDY clustering handles dual dipoles, and I (and Caterina also) have wanted to know about it. Arno?
Makoto
On Tue, Feb 24, 2015 at 7:08 AM, Salim Al-wasity <salim_alwasity at yahoo.com> wrote:

Dears
After decompose my EEG data to components using ICA and estimate their dipoles, some of these dipoles have high residual variance(RV). Therefore I used bilateral dipoles to reduce the RV.1- In (plot component dipoles) options, it gives me only one coordination ever if I have two dipoles. How can I know where these two dipoles are?2- Using a PCA clustering approach, I might find one cluster located at the right hemisphere but it has some dipoles at the left side (bilateral dipoles), Is this cluster correct?
SincerelySalim


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-- 
Makoto Miyakoshi
Swartz Center for Computational Neuroscience
Institute for Neural Computation, University of California San Diego


    

    



-- 
Makoto Miyakoshi
Swartz Center for Computational Neuroscience
Institute for Neural Computation, University of California San Diego


   



-- 
Makoto Miyakoshi
Swartz Center for Computational Neuroscience
Institute for Neural Computation, University of California San Diego


  
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