Dear Norbert,
You should not use w_.. images for contrasts. I think this is
mentioned in the manual. These images violate the assumptions of
random field theory and therefore you cannot get any valid inference
from them. You should always smooth them and use the smoothed
versions, but you can try to experiment with different degrees of
smoothing without re-doing the inversion every time and for this the
w_.. images are useful. Since you did group inversion, you should
already have good overlap in your subjects' activations so
theoretically you should apply only minimal smoothing.
Best,
Vladimir
2009/5/19 Norbert <[log in to unmask]>:
> Hi Vladimir,
>
> First of all thank you for the help of previous days. Another question doing
> 3D. I have done a group inversion of several EEG files and got two types of
> images sw and w. I used the sw in my analysis, but decided to do the same
> for the w type images. However, I can do just the F-test; for a two groups
> t-test I get the information below. Something is out of range I suppose. I
> do not know if the problem is with the w type of my images, surprising given
> that the sw worked well. I also tried different combinations of w images
> entering the t-test but always the same message.
>
> In spm_invTcdf at 93
> In spm_u at 31
> In spm_uc_RF at 30
> In spm_uc at 39
> In spm_getSPM at 686
> In spm_results_ui at 276
> ??? Error using ==> betainc at 42
> X must be in the interval [0,1].
>
> Error in ==> spm_Tcdf at 106
> F(Q) = xQxPos
> -(xQxPos*2-1).*0.5.*betainc(v(Qv)./(v(Qv)+x(Qx).^2),v(Qv)/2,1/2);
>
> Error in ==> spm_P_RF>spm_ECdensity at 157
> EC(1,:) = 1 - spm_Tcdf(t,v);
>
> Error in ==> spm_P_RF at 59
> EC = spm_ECdensity(STAT,Z,df);
>
> Error in ==> spm_uc_RF at 37
> [P P p] = spm_P_RF(1,0,u,df,STAT,R,n);
>
> Error in ==> spm_uc at 39
> u = spm_uc_RF(a,df,STAT,R,n);
>
> Error in ==> spm_getSPM at 686
> uu = spm_uc(0.05,df,STAT,R,n,S);
>
> Error in ==> spm_results_ui at 276
> [SPM,xSPM] = spm_getSPM;
>
> ??? Error while evaluating uicontrol Callback
>
> Norbert Jaučovec
> Filozofska fakulteta,
> Oddelek za psihologijo
> Univerza v Mariboru
> Koročka 160, 2000 Maribor
> Tel: +386 2 2293606
> GSM: +386 41 387834
> [log in to unmask]
> [log in to unmask]
>
>
>
>
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