@pimms.param<EOL><INDENT>def voxel_to_vertex_matrix(mtx):<DEDENT>
return pimms.imm_array(to_affine(mtx, <NUM_LIT:3>))<EOL>
sub.voxel_to_vertex_matrix is the 4x4 affine transformation matrix that converts from
(i,j,k) indices in the subject's image/voxel space to (x,y,z) coordinates in the subject's
cortical surface space.