Can you send me that file? On 29 Jan 2014, at 16:41, Michael <[log in to unmask]<mailto:[log in to unmask]>> wrote: Hi Saad, In the end i could load the matrix with all the fiber counts per pair of voxels (fdt_matrix3.dot) but the intensity of the target mask voxels (4th column of coords_for_fdt_matrix3) is always 0 so i couldn't use your code. Do you know why the intensity of the target mask voxels is not picked up? Does it need to be numbered from 1 to N? The intensity range is currently composed of non-sequential integers. -- Saad Jbabdi University of Oxford, FMRIB Centre JR Hospital, Headington, OX3 9DU, UK (+44)1865-222466 (fax 717) www.ndcn.ox.ac.uk/team/researchers/saad-jbabdi<http://www.ndcn.ox.ac.uk/team/researchers/saad-jbabdi>