[FieldTrip] BEMCP

Debora Desideri deb.desideri at gmail.com
Thu Mar 17 16:13:35 CET 2016


Dear John,
what I am correlating are the lead field produced using subject-specific
realistic FEM head model  or BEM head model and concentric spheres head
model. As Vladimir suggested, this should help me to find the proper inward
shift to apply in order to achieve good results with the BEM model.
Unfortunately, the BEM model still seems not to work properly.
Anyway, given the results of the latest attempts,  I will definitely use
the FEM model for my analysis, even if it is takes much longer to create
the head model and lead fields.
Thanks again!
Best,
Debora


On Thu, Mar 17, 2016 at 3:57 PM, RICHARDS, JOHN <RICHARDS at mailbox.sc.edu>
wrote:

> "The correlation between concentric spheres and FEM (attached) it is not
> so bad” .  I am not sure what you are correlating.  Is this over the time of
> a beamformer model, or over participants with a single-time model?  In
> either case, I think the correlations for the FEM-Concentric spheres are
> bad, many are less < 0.8, and a number are in the range from .9 to .95.
>
> This result confirms the difference in the FEM and concentric-sphere
> models.  These are exacerbated even further when you use a
> subject-specific realistic FEM model and a concentric spheres model.
>
> The results between the BEMCP and concentric spheres suggests that the
> BEMCP model is not working.  Most of the correlations should be positive.
> I have not used correlations as you have, but have done ROIs in an
> individual, and correlated the values of the ROIs over the head for one
> subject, or multiple subjects.  I find higher correlations for the BEMCP
> and Concentric sphere models, than between either of these  and a FEM
> model.  However, in my case I am not using the standard model from FT, but
> using subject-specific BEMCP, concentric spheres, and FEM models.
>
> If the FEM model is working for you, why not use it?
>
> John
>
> ***********************************************
> John E. Richards Carolina Distinguished Professor
> Department of Psychology
> University of South Carolina
> Columbia, SC  29208
> Dept Phone: 803 777 2079
> Fax: 803 777 9558
> Email: richards-john at sc.edu
> HTTP: jerlab.psych.sc.edu
> ***********************************************
>
>
>


-- 

Debora Desideri, PhD Student
BNP Lab - Neurology Department
University Hospital Tübingen
Eberhard Karls University Tübingen
Hoppe-Seyler Str. 3
D-72076 Tübingen
Tel: +49 7071/29 80478
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