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Metric Auto Load

Metric auto load is intended for use with tractography connectivity data. There may be many thousands of metric files for tractography data and loading all of the metric files is neither practical nor in most cases, possible. When the user identifies a node, the voxel corresponding to the node is determined, and a metric file that contains connectivity information for that voxel as the seed point is loaded and displayed.

Metric File Naming

The metric file names must follow a naming convention. Each metric file must be named <anything>Voxel_i_j_k.metric where i, j, and k are the integer voxel indices (for example 00326_Voxel_17_42_15.metric). The alphabetical characters are case insensitive.

Display Control


Two auto loaders are available. The auto loaded metric data is only displayed on the Display Surface, not all surfaces.

To enable metric auto loading

  1. On the Display Control's Overlay/Underlay Surface page, set one of the Surface Overlays to Metric (this requires that metric data is loaded).
  2. Go to the Display Control's Metric Miscellaneous Page.
  3. Enable one or both Metric Auto Loader(s) by selecting the checkbox(es) labeled Auto Load Metric
  4. Press the Metric Directory button and select the directory that contains the specially named metric files.
  5. Choose the Anatomy Volume that contains voxel indices corresponding to the metric file names.
  6. Set the Volume Intersect Surface to the fiducial surface that properly intersects with the selected Anatomy Volume.
  7. Set the Display Surface to the surface on which the metric data is displayed.

When a node is identified, the node's coordinate is determined using the Volume Intersect Surface selected in the Auto Load Metric section. This coordinate is then converted to voxel indices using the stereotaxic coordinates of the Anatomy Volume selected in the Auto Load Metric section. These voxel indices are used to find the appropriate metric file for loading and displaying. Since the fiducial surface for intersection with the Anatomy Volume is selected on the here, nodes can be identified on any surface for auto-loading metric files.

To auto load metric files

  1. Verify Caret is in View Mode (the default mouse mode)
  2. Identify a node on any surface (fiducial, inflated, flat, etc).

If no metric file is found that matches the voxel indices, an error message is displayed in the terminal window.


  • Metric data must be loaded and at least one surface overlay must be set to metric for Metric Auto Load to function.
  • Only Coloring of the Display Surface is affected.
  • Scenes do not support metric auto load.
  • If the Replace Previously Loaded Column checkbox is checked, the previously auto-loaded column is replaced. Otherwise, when an auto loaded metric file is loaded and displayed, the last column is selected and displayed.
  • When an auto load metric file is loaded, its contents are appended to the currently loaded metric data. The Spec File is NOT updated to include the auto load metric file.



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