Hi Katja,
The thresholds only display values greater than the threshold value.
So you could use the metric math dialog (Attributes Menu-Metric-
Mathematical Operations to convert your p-values to (1 - p) values
(I may have seen this called Q) and then set the threshold to
0.999. On the Metric Math Dialog, set both Column A and Result to
your metric data. Check the button next to Multiply Column A by
Scalar, enter -1.0 for the value, and press the Apply button. Next,
check the button next to Add Scalar to Column A, enter 1.0 for the
value, and press the Apply button.
To find clusters use Attributes Menu-Metric-Clustering and
Smoothing. Press the Help button and it will describe how to use the
clustering option. You can also use the threshold values for the
clusters to find only nodes with values less than 0.001.
--
John Harwell
[EMAIL PROTECTED]
314-362-3467
Department of Anatomy and Neurobiology
Washington University School of Medicine
660 S. Euclid Ave.Box 8108
St. Louis, MO 63110 USA
On Jun 15, 2007, at 9:04 AM, Katja Umla-Runge wrote:
Hello everyone,
I'm a new Caret user and am currently trying to display t-contrast
fMRI images (SPM99) in Caret. What kind of threshold does Caret
require (Display control -- metric -- threshold Pos)? I performed
uncorrected t-tests in SPM with p .001. Is 0,001 the value to
insert? And how would you let Caret know that a threshold refers to
correction for multiple comparisons? If you only want those voxels
displayed that exceed a given cluster size (e.g. minimal cluster
size = 20 adjacent voxels), how would you go about?
Thank you for your help
Katja
--
Dipl.Psych. Katja Umla-Runge
Saarland University
Department of Psychologyphone: +49 - (0)681 - 302 4643
P.O.Box 151150 fax: +49 - (0)681 - 302 4049
D-66041 Saarbrueckenemail: [EMAIL PROTECTED]
www.BrainCog.de
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