LLN, le 6/01/06
Dear Suzanne,
This may have to do with the cluster size (100 voxels) you set. The
number of results displayed is a function of both p and k. Check with
k=0 at p<0.001 if you want to be sure.
Hope this helps,
Mauro
>In running a contrast on PET data, I set the threshold to be p<0.001 for 100
>contiguous voxels, and I find in looking at the volume or cluster Pvalue
>results that there are no clusters above that threshold. No until I lower
>the thresold to p<0.005 (100 voxels again) do I see results. However, the P
>uncorrected values listed in both the voxel-level as well as cluster-level
>are less than 0.001. Why did these voxel-level statistics not appear when
>p<0.001 was used?
>
>Thanks in advance,
>Suzanne Baker
--
_____________________________________
Help fighting hunger: http://www.hungersite.com
Just click your mouse and sponsors of The Hunger Site donate a
serving of food to a person in need - at no cost to you.
______________________________________
Mauro PESENTI
Research Associate, National Fund for Scientific Research (Belgium)
Unite de Neurosciences Cognitives
Departement de Psychologie
Universite Catholique de Louvain
Place Cardinal Mercier, 10
B-1348 Louvain-la-Neuve
tel.: +32 (0)10 47 88 22
fax: +32 (0)10 47 37 74
E-mail: [log in to unmask]
http://www.nesc.ucl.ac.be
http://www.nesc.ucl.ac.be/mp/pesentiHomepage.htm
|