[FieldTrip] Cluster-based permutation tests for between-subject design

[Luis Garcia Dominguez]

Hello all,

I have a problem when using the ft_dipolefitting function in two different
versions. The old version of the function gives me the accurate result and
a low residual variance (RV) while the new version produce a totally off
localization with high RV.
I have attached a .mat file with the two inputs to the function (cfg and
timelock) for easy reproducibility.

Steps:

1) load('input_variables.mat')  % the file attached
2) fix the path to the standard bem file in the appropiate field of cfg as:
cfg.hdmfile = [path 'standard_bem.mat]
3) run: source = ft_dipolefitting(cfg, timelock);

In the version that comes with EEGlab 11.0.4.4b (which shows a revision =
'$Id: ft_dipolefitting.m 5439 2012-03-12 13:17:15Z giopia $';)
a local minimun is found and the dipole is:

>> source.dip

ans =

    pos: [51.7641 24.5471 -35.4362]
    mom: [3x1 double]
    pot: [27x1 double]
     rv: 0.0218

While in the most recent fieldtrip version:

ans =

    pos: [-45.2455 -86.2421 -15.2132]
    mom: [3x1 double]
    pot: [27x1 double]
     rv: 0.5848


I have intracranial electrodes that show that the solution from the old
dipolefitting function is the right one.
Can you please, help me to understand what is the source of this huge
difference?
Thanks!

On 6 January 2015 at 02:13, Yoni Levy <yoniilevy at gmail.com> wrote:

> Dear Eric,
>
> Following up on the thread from about 2 months ago, in your reply (in
> FAQs:
> http://fieldtrip.fcdonders.nl/faq/how_can_i_test_an_interaction_effect_using_cluster-based_permutation_tests),
> when you mention the mixed between-within-subjects design, I assume
> that you refer to a design with two subjects groups which are of equal size
> (e.g. 12 participants vs 12 participants, and not 14 participants vs 12
> participants). I assume that in the latter case (unequal groups' size),
> testing the interaction effect would not be possible; correct?
>
> Thanks,
> Yoni
>
>
>
>
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>



-- 
Luis
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