Thanks Doug. I only now gather that the statistical maps are displayed in terms of the negative common (base 10) logarithm of the p-value. Two questions: 1) I'm probably wrong here, but if they were displayed (and thresholded) in terms of the corresponding *t*-value instead, would that not be more convenient since you could also see at a glance the direction of the effect (i.e. whether group A or B has the greater thickness), rather than having to check the group means in the output files of the design? 2) given that p-values lie between 0 and 1, -log10(p) should be between 0 and infinity. How come, then, that the colour-bar also shows negative values?
Tudor
On 4 February 2014 17:09, Douglas N Greve greve@nmr.mgh.harvard.edu wrote:
You have the "Min" set to 2 which means that you are not seeing cluster less significant than p=.01. Try setting it to 1.3 (p=.05) doug
On 02/02/2014 01:55 PM, Tudor Popescu wrote:
Dear Freesurfer experts,
I ran a QDEC analysis for structural data and found, after Monte-Carlo correction@0.05, one significant cluster, annotated as "postcentral" (see screenshot attached). The stats associated with it are displayed in the terminal, however the statistical map on the template brain is blank.
Also, when I press the "Find Cluster and Go To Max" button, I receive an error that no stats can be generated for that cluster.
Not sure if it's relevant, but my dependent variables of interest in this analysis were thickness and local gyrification index (lGI). It seems I'm getting the above problem only when lGI is the DV, and whether or not there is a group factor among the categorical predictors. I do have, however, lGI analyses where the significant cluster shows up fine both on the template and in the terminal window.
Can anyone help? Many thanks in advance!
Best wishes, Tudor
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