Doug and freesufer list.

 When I load the sig map in tksurfer i know that the CWP is displayed as the -log(10)p; however, I am not asking about visualization or the CWP. The newest version of the wiki does a great job in explaining the p values.  I am only asking about the sig.cluster.summary report. It makes since that "The Max is the vertex-wise maximum and is bounded below by the vertex-wise threshold." But then what units is it in?

When I was not sure what the second column was I turned to visualization. After, loading both the sig.cluster.mgh and the group descriptor file in tksurfer and  then selecting a vertex in the region with the most significance, which is  based off of the CWP, it displays a scatter plot. The scatter plot does not have a label for the y-axis; however, the highest point on the y-axis is similar to the max, in column 2,  of the sig.cluster.summary report.  On the older wiki, there was a paragraph describing how the y was thickness. But, the sig.cluster.summary report does not have any labels for the second column. But, since the value was similar to the y-axis I began to interpret it as thickness, but wanted to clarify with the freesurfer team.

- Judith


On Thu, Jun 4, 2009 at 11:15 AM, Douglas N Greve <greve@nmr.mgh.harvard.edu> wrote:
It is the maximum vertex-wise -log10(p) found in the cluster. Why do you think otherwise? You should be able to load the sig map into tksurfer and go to that vertex to find out.

doug

Judith Segall wrote:
Thanks, for you responses Doug and Pratap. But, both of your responses need more clarification, because I believe that we are not all referring to the same 'max'.

Doug:

 I understand that when I display the sig.cluster.mgh that the a CWP value of 0.0001 would be displayed as a 4 by the color bar in tksurfer, since it is the -log10(p). However, in this case, which is about the cluster growing summary, the -log10(p) of the CWP does not equal the Max. Max is -3.312 and the CWP is 0.08250. Or an additional example form another sig.cluster.summary, where the Max is -4.310 and the CWP is 0.0192.
ClusterNo  Max   VtxMax   Size(mm^2)  TalX   TalY   TalZ    CWP      CWPLow    CWPHi    NVtxs   Annot
  1           -4.310   40526    376.78        -12.0  -66.1    5.4    0.01920  0.01750       0.02100   706      lingual

In Pratap's email his answer to my question of what is the max in the CWP is,  "Yes thickness. The MAX indicates the maximum -log10(pvalue) in that cluster." Which, is stating that it is both the thickness and the pvalue. I really think that it is thickness measure, but need some clarification from mgh.

So, is the Max in column 2 of the cluster growing summary report, from monte carlo simulations, thickness?

Thanks,

Judith S.

On Thu, Jun 4, 2009 at 9:25 AM, Douglas N Greve <greve@nmr.mgh.harvard.edu <mailto:greve@nmr.mgh.harvard.edu>> wrote:

   It will be whatever you used as input. In this case, it is the
   -log10(p) value of the maximum in the cluster (not the thickness
   value).

   doug


   Pratap Kunwar wrote:

       Hi Judith,

       Yes thickness. The MAX indicates the maximum -log10(pvalue) in
       that cluster.

       
           Hi all. After looking over our monte-carlo results, I a
           simple question
           about the sig.cluster.summary output.

           Is the " Max" in column 2 below a measurement of thickness?
           thickness, is the correct interpretation the following:
           the most
           significant
           cluster is in the laterorbitofrontal region.
             
       yes at lateral orbital frontal.
       The max vertex in that
       
           cluster
           has an average thickness of 3.312 mm and the negative
           directionality
           indicates that it is thinner in that region than in the
           fsaverage (from
           freesufer) used in the group analysis/simulations?
             
       yes you are correct.
       
           If it does not refer to thickness, is it a statistic, etc?

           # Minimum Threshold 2
           # Maximum Threshold infinity
           # Threshold Sign    abs
           # AdjustThreshWhenOneTail 1
           # Area Threshold    0 mm^2
           # CSD thresh  2.000000
           # CSD nreps    10000
           # CSD simtype  mc-z
           # CSD contrast lh-Avg-thickness-CAQ-CCI
           # CSD confint  90.000000
           # Overall max 2.05497 at vertex 92846
           # Overall min -3.3122 at vertex 60632
           # NClusters          11
           # Total Cortical Surface Area 65416.6 (mm^2)
           # FixMNI = 1
           #
           # ClusterNo  Max   VtxMax   Size(mm^2)  TalX   TalY   TalZ
              CWP
           CWPLow    CWPHi   NVtxs   Annot
             1       -3.312   60632    278.00    -15.2   47.7  -15.4
            0.08250
           0.07900  0.08600   341  lateralorbitofrontal
             2       -3.231   51202    118.54    -39.5   24.9   16.9
            0.53620
           0.52980  0.54260   212  rostralmiddlefrontal
             3       -3.229   67407    163.06    -19.2   12.0   46.9
            0.36360
           0.35740  0.36980   337  superiorfrontal
             4       -2.463  117667     37.51    -47.8  -50.8    8.0
            0.63240
           0.62620  0.63860    79  bankssts
             5       -2.379  151243     12.92    -30.9  -42.8   36.6
            0.63240
           0.62620  0.63860    38  superiorparietal

           I am trying to finish writing up my results and just need
           answer to this
           question to continue.

           Thanks,

           Judith S.
           Mind Research Network
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   --    Douglas N. Greve, Ph.D.
   MGH-NMR Center
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Douglas N. Greve, Ph.D.
MGH-NMR Center
greve@nmr.mgh.harvard.edu
Phone Number: 617-724-2358 Fax: 617-726-7422

In order to help us help you, please follow the steps in:
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