Whiteordinate
    Whiteordinate
      is a brain white matter
      location.  It is generally represented by a white matter
      voxel, though in principle, it can also be represented by a
      surface vertex (node).  Whiteordinates represent a subset of
      all brainordinates. 
      In a CIFTI file,
      a list of whiteordinates need not fill the entire grid of the 'N x
      M x O' volumetric dimensions.