[Marsbar-users] using conjunction activation to define ROI

[<cs...@pu...>]

Hi MarsBar users,

I'm new to Marsbar. I want to use the activation of conjunction analysis to
define ROI.
I used the procedure in the following way:

First I created a binary mask for the conjunction image in the way below:
               MarsBar--> Definition-->Build
                       -->Type of ROI -->image (selecting conjunction image)
                       --> maintain as binary mask?---Yes
                       --> apply function to image? ---> Yes
                       --> function to apply to image-->img > 0.0
                       --> description of ROI--> whatever I like
                       --> label for ROI--> whatever I like
                       --> save to whatever directory I want

Then combine this binary mask with whatever predefined MNI.roi in AAL together
as follows:
         MarsBar -> ROI definition-> Transform -> Combine ROI (r1 & r2) 
                            -->selecting conjunction image I just created and    
                        MNI.roi in AAL which I'm interested in, such as SFG_L  
                                
                            --> Function to combine ROI: r1 & r2
                                             --> Description of ROI: eg.SFG_L
                                             --> Label of ROI: eg.SFG_L
                                             --> Save 

After that, MarsBar-> Definition->to view the combination. Using this to
determine a x,y, z coordinates to define my ROI. Should anyone tell me procedure
above is correct? if not, what should I do? 

Also, I found the combination is a range. Should I use the numbers of "centre of
mass" as x,y,z coordinates or pick up whatever numbers of the crosshair is
pointing (which is still in the range)? Thanks in advance!

Regards,

Chunhong