I used SPM8 for my experiment. I manipulated three factors (e.g., factor A, B, C) in my experiment. The activation maps under factor A was used as a mask to constrain the effects of factor B and factor C. The problem is that the factor A and factor B and factor C cannot be put in the same model at second level analysis. I tried to put the .img file resulting from factor A across participants in the “explicit mask” in the second level analysis. However, the estimation stopped by showing no inmask voxels. I searched through forum and did not find any useful solutions. Can someone help me out? Moreover, is the threshold masking related to the p value? If not, how should I set criteria for the activation map of the mask?
I did notice that one person in the forum suggested that one can create an activation maps in which the factor B is modeled with the mask of factor A in first level analysis. Then, submit the resulting .img file into second level analysis. My question is how to create and save the img file.
Finally, I posted a question regarding how to export beta values over multiple coordinates a week ago. However, no one provide any answers. I wonder whether it is due that no one has the answer or due to that there already is an answer in the forum.
Thank you for your patience and advice.