Dear Stefan,
Thankyou for your reply.
>
>Could you check, whether the uncorrected p-values are zero? You can do
>this by right-clicking on the value. The true value will be output in
>the matlab window. Note that there cannot be a smoothness estimate into
>z-direction, because you have only 1 slice.
>
I have checked the values and I apologise, you are right, the
uncorrected p-values are non-zero.
Even though there should be no smoothness estimate for the z
direction it does seem to be given as infinity. If this
incorrect z-direction smoothness is input to the calculation of the
corrected cluster probabilities will it not result in the values
given below?
>> Cluster-level p uncorrected were all 1.0
>> p corrected were all 0.648
>> k were all NaN
>
>This is not what one would expect. I checked spm_P and spm_getSPM, which
>are the routines used for computing the corrected p-value for cluster
>size and it seems to me that the 2D-case is probably not properly taken
>care of, but I'm not sure yet.
>
Thanks again for your help. I hope my reply will give more of an insight
to the problem. If you need any more figures from my analysis don't
hesitate to ask.
Yours,
Tom.
=================================================
Mr.Tom Barrick,
PhD Student,
Magnetic Resonance Image Analysis Research Centre,
University of Liverpool,
Pembroke Place, PO BOX 147,
Liverpool, L69 3BX.
Tel : +44 (0) 151 794 5634
Fax : +44 (0) 151 794 5635
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