[Eeglablist] Inter-Electrode Distance

[Iman M.Rezazadeh]

Hi ,
Thanks for your comments. It is obvious thatIF WE HAVE ACTUAL CAP then we
can  measure the inter electrode distance from that.  
But what if you do not have the cap or you convert your EEG recoding montage
virtually to other montages ( for example in BESA you can do that from 128
electrode montage to 81 or 27 montage) . In that case there is no cap
manufacturer or actual cap or net!!! 

P.S: You might say I should ask BESA about that:)
BR
Iman

-----Original Message-----
From: Tarik S Bel-Bahar [mailto:tarikbelbahar at gmail.com] 
Sent: Tuesday, December 18, 2012 6:42 PM
To: Iman M.Rezazadeh
Subject: Re: [Eeglablist] Inter-Electrode Distance

Greetings Iman,

If the EEG electrodes were part of an EEG cap or net sold by a company, that
company should have very specific information about inter-electrode
distances on an average head. You may also be able to get true 3D location
points for such a net or cap from a lab that had done 3D electrode
registration using that cap or net.
Also, as you can note, the more specific you are on the list, the better!

Best wishes for your work!



On Tue, Dec 18, 2012 at 6:45 PM, Iman M.Rezazadeh <irezazadeh at ucdavis.edu>
wrote:
> Simon!
>
> You are right. But what if we do not have access to the subjects and 
> the data was recorded before.
>
> Best,
>
> Iman
>
>
>
>
>
> From: Simon Finnigan [mailto:finnigan.simon at gmail.com]
> Sent: Tuesday, December 18, 2012 3:13 PM
> To: Iman M.Rezazadeh
> Cc: Tim Mullen; UCSD EEG List
> Subject: Re: [Eeglablist] Inter-Electrode Distance
>
>
>
> Dear All,
>
>
>
> Would it be the craziest idea you've ever heard if I were to suggest 
> you just get a tape measure, place an electrode cap on a head, and 
> measure the inter-electrode distances?!
>
>
>
> Simon
>
>
>
> On Tue, Dec 18, 2012 at 7:25 PM, Iman M.Rezazadeh 
> <irezazadeh at ucdavis.edu>
> wrote:
>
> Thanks Tim for your response ! and your two cents: )
>
> ·        Ok let me be clear. If we have electrode location file and fit
> anatomical head model ( not spherical ) the results will different . 
> So, my question is " Is there ANY ANATOLICAL MODEL based on the 
> electrode locations/labels that can help us to measure the inter-electrode
distance?"
> I have done a test over 3 different individual scalp and there is +/- 
> 4 cm difference between using spherical model and real head on average.
>
> ·
>
> Best,
>
> Iman
>
> From: Tim Mullen [mailto:mullen.tim at gmail.com]
> Sent: Tuesday, December 18, 2012 1:04 AM
> To: Iman M.Rezazadeh
> Cc: Makoto Miyakoshi; UCSD EEG List
> Subject: Re: Inter-Electrode Distance
>
>
>
> No worries, Iman -- just my two cents :) The email mailing list format 
> is also not the easiest format to search and follow up on old posts. 
> But I do think it helps reduce everyone's inbox clutter (and likely 
> ensures you get a faster/better response) if new posts make clear how 
> the given problem is not addressed by previously posted solutions.
>
>
>
> In the 2010 thread Arno describes a solution for the electrode 
> distance on the scalp assuming a spherical head model, and this is 
> implemented in the function elec_distance.m, which you referred to. 
> Asking "does elec_distance.m work properly?" is something you can 
> probably quickly answer yourself :) Do you have reason to think this 
> function is not working properly? Is this not the solution you were 
> hoping for? The more specific and clear your question, the more help can
be provided by the community.
>
>
>
> Tim
>
>
>
> On Mon, Dec 17, 2012 at 4:51 PM, Iman M.Rezazadeh 
> <irezazadeh at ucdavis.edu>
> wrote:
>
> Tim, I have   searched the forum and if you look at my email you can see
> that I mentioned the function name as well. Also what Steve pointed at 
> is sth different !
>
> Anyhow, thanks for the reminder for reading the archives and internet 
> search J  and I would add reading more carefully the emails J
>
> Iman
>
>
>
> From: Tim Mullen [mailto:mullen.tim at gmail.com]
> Sent: Monday, December 17, 2012 4:18 PM
> To: Makoto Miyakoshi
> Cc: Iman M.Rezazadeh; UCSD EEG List
> Subject: Re: Inter-Electrode Distance
>
>
>
> Iman, a general rule of forums and mailing lists (such as EEGLAB) is 
> to first search the forum/list archives for a solution. In this case, 
> the question has been addressed at least once before: i.e. search for 
> 'inter-electrode distance' in the subject lines for 2010 -- 
> http://sccn.ucsd.edu/pipermail/eeglablist/2010/subject.html. If you 
> can't find a solution in the archives (or after a little internet 
> searching), then by all means post to the list :)
>
>
>
> Also, I just saw that Steve noted this topic came up a few days ago on 
> the list...
>
>
>
> Tim
>
>
>
> On Mon, Dec 17, 2012 at 3:54 PM, Makoto Miyakoshi 
> <mmiyakoshi at ucsd.edu>
> wrote:
>
> Dear Iman,
>
>
>
> Why don't you try it first since the function is already there :-)
>
>
>
> Makoto
>
>
>
> 2012/12/17 Iman M.Rezazadeh <irezazadeh at ucdavis.edu>
>
>
>
> Hi,
>
> Could you please let me know how can I measure the inter-electrode 
> distance on the head surface? Does elec_distance.m woeks properly?
>
>
>
> Iman M.Rezazadeh, PhD
>
> Postdoctoral Research Fellow
>
> Center for Mind and Brain
>
> University of California, Davis
>
> irezazadeh at ucdavis.edu
>
> Cell:310-490-1808
>
> Skype: Imanmr
>
>
>
>
>
>
>
> --
> Makoto Miyakoshi
> JSPS Postdoctral Fellow for Research Abroad Swartz Center for 
> Computational Neuroscience Institute for Neural Computation, 
> University of California San Diego
>
>
>
>
>
> --
> ---------  αντίληψη -----------
>
>
>
>
>
> --
> ---------  αντίληψη -----------
>
>
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