Hi Harry,
1. for a longitudinal qdec table format the first column fsid is the tp id (cross), the second column fsid-base the name of the base. From that, scripts will automatically create the tp.long.base directly names internally , if needed. An example long qdec table is here: http://surfer.nmr.mgh.harvard.edu/fswiki/FsTutorial/LongitudinalTutorial_fre... You see that the first column does not contain .long.<base> .
2. standard qdec tables do not group time points into subjects, so they don't have the second column. It does not matter what you name these qdec files have, you can call them cross.qdec.table.dat or qdec.table.dat or myfilenameisbetter.yeah
3. the cross.qdec.table.dat from the tutorial is a reduction of a longitudinal qdec table, to a table that has only a single row for each subject. This is necessary to use it in Qdec. In that tutorial we describe the 2-stage model , where first you compute the rate of change within each subject, then you compare those change maps across subjects / groups etc with standard methods (glmfit or qdec).
Hope that helps.
Cheers, Martin
On 04/14/2014 10:51 PM, Harry Hallock [hhal5293@uni.sydney.edu.au] wrote:
Addtionally what is the difference between using:
*qdec.table.dat* from https://surfer.nmr.mgh.harvard.edu/fswiki/FsTutorial/QdecGroupAnalysis_freev...
and
*cross.qdec.table.dat *from https://surfer.nmr.mgh.harvard.edu/fswiki/FsTutorial/LongitudinalTutorial_fr...
if ultimately im just trying run a simple analysis to see any differnces amongst 1 group of ppl at 2 timepoints.
Thanks,
Harry
*Harry Hallock*| MPhil Candidate Regenerative Neuroscience Group | Brain & Mind Research Institute *THE UNIVERSITY OF SYDNEY*
Room 408, Level 4, M02K | 94 Mallett St Camperdown | NSW | 2050| Australia *T +*61 2 9114 4138 F +61 9351 0930 *E *hhal5293@uni.sydney.edu.au*| W *www.rng.org.au
*From:* freesurfer-bounces@nmr.mgh.harvard.edu freesurfer-bounces@nmr.mgh.harvard.edu on behalf of Harry Hallock [hhal5293@uni.sydney.edu.au] hhal5293@uni.sydney.edu.au *Sent:* Tuesday, 15 April 2014 12:37 PM *To:* freesurfer *Subject:* [Freesurfer] long.qdec.table.dat
Hi all,
I am currently doing longitundal processing. I have gone through the turtoial but still cannot find the answer.
When creating a long.qdec.table.dat, should the first column entitled "fsid" be long or cross data?
Cheers,
Harry
*Harry Hallock*| MPhil Candidate Regenerative Neuroscience Group | Brain & Mind Research Institute *THE UNIVERSITY OF SYDNEY*
Room 408, Level 4, M02K | 94 Mallett St Camperdown | NSW | 2050| Australia *T +*61 2 9114 4138 F +61 9351 0930 *E *hhal5293@uni.sydney.edu.au*| W *www.rng.org.au
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