On Mon, 06 Dec 2004 14:23:54 +0100, John Ashburner
<[log in to unmask]> wrote:
(cut)
> Because the images are in the SPM format,
> rather than the FSL format, you would get blobs in SPM, but not FSL.
(/cut)
Interestingly it was FSL that gave me blobs where SPM wouldn't. I hope
that doesn't ruin my credits with the SPM community :-)
I'll try and track it down - I still believe it has to be a mess-up on my
part.
Best regards,
Cornelius Werner
>> just out of curiosity, I analyzed a fairly complex (and long) erfMRI
>> experiment with a 3x3 factorial design with both SPM2 and FSL3.2b. I
>> tried
>> to keep everything as close to the other package as possible, i.e. I
>> adjusted both smoothing kernels to 5mm, set the high pass filter to
>> 128s,
>> used gamma function + temp. derivative in FSL (standard delay) /
>> canonical
>> hrf + tdv in SPM2, entered identical onset vectors, specified identical
>> contrasts and so on. I set the duration for my events to the actual 1.5
>> seconds in both packages, as FSL doesn't allow 0-durations.
>> Now one of the packages gave me "blobs" on a
>> corrected-for-multiple-comparisons level of 0.05, where the other didn't
>> show anything worth mentioning on a uncorrected p=0.001 level. Is that
>> possible at all, given the similarity of the statistics? Has anyone
>> experienced something similar? I am aware of the comparison done by
>> Bianciardi et al (NeuroImage 2004), but differences were marginal at
>> best...!
>
--
Cornelius Werner
Institut fuer Medizin (IME)
AG Kognitive Neurologie
Forschungszentrum Juelich
52425 Juelich
Germany
Tel. +49-(0)2461-61-8609
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