Hi

we are using 3dClustSim to correct for multiple comparsions. We are using the following steps to interpret the results and I wanted to make sure if this is correct?


We use following 3dClustSim command and get the result below

# 3dClustSim -fwhmxyz 8.011376833 8.060715833 7.486849833 -mask /nfs/mint/MNIs/MNI_avg152T1_mask_2mm+tlrc. -athr .05 -pthr .025 .005 .0025 .0005 -NN 123 -prefix POMP_FWHMx_8211
# Grid: 91x109x91 2.00x2.00x2.00 mm^3 (239901 voxels in mask)
#
# CLUSTER SIZE THRESHOLD(pthr,alpha) in Voxels
# -NN 1 | alpha = Prob(Cluster >= given size)
# pthr | .05000
# ------ | ------
0.025000 471.5
0.005000 148.7
0.002500 103.1
0.000500 49.6


We want to know which clusters are significant (multiple comparison corrected) at p < 0.05
So according to the alphasim result above, should we threshold the result maps in AFNI at a) 0.025 or b) 0.05 ( ie: 0.025 X 2 - to convert 2 tailed to 1 tailed)

Thanks so much for your help and sorry for the silly question!



Edited 1 time(s). Last edit at 09/28/2015 08:44PM by prerona.