I have a voxel ROI overlayed on top of a gray matter mask. I am working on co-registering the gray matter mask to the T1. The T1 is in 192 X192 X 144 matrix. However, the gray matter mask is 256 X 256 X256.

I run into the following error when trying to coregister: Requested 101197x97754 (73.7GB) array exceeds maximum array size preference. Creation of arrays greater than this limit may take a long time and cause MATLAB to become unresponsive. See array size limit or preference panel for more information.
Cannot access file "U:\PAD_Data\fMRI\rsFC_T1\LP201\LP201_GM_all.nii".