Instead of calculating the average you should calculate the min of the
two conditions (con1,con2), this is the basis of the conjunction analysis.
Michael
Am 10.08.2016 um 04:06 schrieb MCLAREN, Donald:
> Marek,
>
> What the reviewer is asking for is not possible because the conjunction
> does not produce a con_ image. Without the con_ image, you can't do the
> second-level analysis.
>
> I think what the reviewer is asking for is to create a contrast of the
> average of the two conditions and to test if the average of the two
> conditions is different between the groups.
>
> Best Regards,
> Donald McLaren, PhD
>
>
> On Wed, Aug 3, 2016 at 8:35 AM, Marek Wypych <[log in to unmask]
> <mailto:[log in to unmask]>> wrote:
>
> Dear SPMers,____
>
> We performed an experiment on readers and pre-readers with speech
> and print conditions. On second level analysis we computed null
> conjunction for the 2 contrast in each group (one sample t-test)
> which produced significant activation in readers while not in
> pre-readers. However, when the paper was sent to review one of the
> reviewers wanted us “to compute the conjunction of print and speech
> on the first level and put these contrasts into a 2-sample t-test on
> the second-level”.____
>
> However we came across some difficulties. If we save thresholded SPM
> map from each subject when performing null conjunction in SPM
> contrast manager and feed these maps to 2^nd level the model cannot
> be estimated and there is an error saying “there are no inmask
> voxels” (even though we used very lenient p<0.05 uncorrected
> threshold for the 1st level conjunction). Is there a better way of
> doing multisubject conjunction?____
>
> Thank you in advance,____
>
> Marek
>
>
>
>
> --
> Marek Wypych PhD
> Laboratory of Brain Imaging (LOBI)
> Neurobiology Center
> Nencki Institute of Experimental Biology
> Pasteur 3, 02-093 Warsaw, Poland
> Tel.: +48 22 5892 550
> http://lobi.nencki.gov.pl/
>
>
--
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Dr. Michael Erb
Department of Biomedical Magnetic Resonance
University of Tübingen
Hoppe-Seyler-Str. 3
72076 Tübingen, Germany
Tel.: +49(0)7071/2987753 priv. +49(0)7071/61559
Fax.: +49(0)7071/294371
e-mail: <[log in to unmask]>
www:
http://www.medizin.uni-tuebingen.de/Forschung/Kliniken/Radiologie/Biomedizinische+Magnetresonanz.html
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