Using Workbench Command

TAKE GRADIENT OF A CIFTI FILE
   wb_command -cifti-gradient
      <cifti> - the input cifti
      <direction> - which dimension to take the gradient along, ROW or COLUMN
      <cifti-out> - output - the output cifti

      [-left-surface] - specify the left surface to use
         <surface> - the left surface file

         [-left-corrected-areas] - vertex areas to use instead of computing
            them from the left surface
            <area-metric> - the corrected vertex areas, as a metric

      [-right-surface] - specify the right surface to use
         <surface> - the right surface file

         [-right-corrected-areas] - vertex areas to use instead of computing
            them from the right surface
            <area-metric> - the corrected vertex areas, as a metric

      [-cerebellum-surface] - specify the cerebellum surface to use
         <surface> - the cerebellum surface file

         [-cerebellum-corrected-areas] - vertex areas to use instead of
            computing them from the cerebellum surface
            <area-metric> - the corrected vertex areas, as a metric

      [-surface-presmooth] - smooth on the surface before computing the
         gradient
         <surface-kernel> - the size of the gaussian surface smoothing kernel
            in mm, as sigma by default

      [-volume-presmooth] - smooth on the surface before computing the gradient
         <volume-kernel> - the size of the gaussian volume smoothing kernel in
            mm, as sigma by default

      [-presmooth-fwhm] - smoothing kernel sizes are FWHM, not sigma

      [-average-output] - output the average of the gradient magnitude maps
         instead of each gradient map separately

      [-vectors] - output gradient vectors
         <vectors-out> - output - the vectors, as a dscalar file

      [-surface] - repeatable - specify a surface by structure name
         <structure> - the surface structure name
         <surface> - the surface file

         [-corrected-areas] - vertex areas to use instead of computing them
            from the surface
            <area-metric> - the corrected vertex areas, as a metric

      Performs gradient calculation on each component of the cifti file, and
      optionally averages the resulting gradients.  The -vectors and
      -average-output options may not be used together.  You must specify a
      surface for each surface structure in the cifti file.  The COLUMN
      direction should be faster, and is the direction that works on dtseries.
      For dconn, you probably want ROW, unless you are using -average-output.

      The <structure> argument to -surface must be one of the following
      strings:

      CORTEX_LEFT
      CORTEX_RIGHT
      CEREBELLUM
      ACCUMBENS_LEFT
      ACCUMBENS_RIGHT
      ALL_GREY_MATTER
      ALL_WHITE_MATTER
      AMYGDALA_LEFT
      AMYGDALA_RIGHT
      BRAIN_STEM
      CAUDATE_LEFT
      CAUDATE_RIGHT
      CEREBELLAR_WHITE_MATTER_LEFT
      CEREBELLAR_WHITE_MATTER_RIGHT
      CEREBELLUM_LEFT
      CEREBELLUM_RIGHT
      CEREBRAL_WHITE_MATTER_LEFT
      CEREBRAL_WHITE_MATTER_RIGHT
      CORTEX
      DIENCEPHALON_VENTRAL_LEFT
      DIENCEPHALON_VENTRAL_RIGHT
      HIPPOCAMPUS_LEFT
      HIPPOCAMPUS_RIGHT
      HIPPOCAMPUS_DENTATE_LEFT
      HIPPOCAMPUS_DENTATE_RIGHT
      INVALID
      OTHER
      OTHER_GREY_MATTER
      OTHER_WHITE_MATTER
      PALLIDUM_LEFT
      PALLIDUM_RIGHT
      PUTAMEN_LEFT
      PUTAMEN_RIGHT
      THALAMUS_LEFT
      THALAMUS_RIGHT