Methods for analysis of multisubject studies

ROI measures : comparisons between various methods of assesing the intesnity of activations within the ROI, : n, p, s, q,Q,r, Q1, ........

this region is most precise but very labor intensive

by choosing regions in the uniform Talairach space, in this case regions are defined as composed of small 8x8 mm rectangular "bricks" using ROI3Ddef

this method is carrying an arror due to misregistration in the Talairach space, this error

in location can approach 10 mm.

DoRegions program used to calculate ROI measures can greate various intensity measures (calculated by the get_region3D function) :

n - number of "active" voxels
s - sum of intensities of active voxels (intensity is defined by varioable main_stat while active status by tcut_stat, those mayne two different maps, e.g. t-statistics and signal change)
r = s/n
R - number of voxels in the ROI that were not eliminated from analysis e.g. by intensity thresholding
q = n/ROIsize*image_size (n normalized by region size)
Q = n/total_n/ROIsize*image_size (n normalized by region size and total number of activations in the whole brain)
Q1 = n/total_n*image_size (n normalized by region size and total number of activations in the whole brain)
Q2 = s/total_n/ROIsize*image_size (s normalized by region size and total number of activations in the whole brain)
Q3 = s/total_n*image_size (s normalized by region size and total number of activations in the whole brain)
Q4 = s/ROIsize*image_size (n normalized by region size)
Q5 = n/total_n/ROIcount*image_size (n normalized by region size and total number of activations in the whole brain, here ROIsize is replaced by number of voxels in the ROI that actually carry signal, are not tresholded)
Q6 = s/total_s/ROIcount*image_size (s normalized by region size and total number of activations in the whole brain, here ROIsize is replaced by number of voxels in the ROI that actually carry signal, are not tresholded)
x,y,z - coordinates of the center of mass of activations within ROI

Composite / ROI comparison: to obtain the objective comparison between those two approaches - difficult because they answer different questions but still very important question!
Composite Maps : The goal is to compare the efficiency of various methods of making composite images