FCD/FCSΒΆ

_images/FCD_new.png

FCD is short for Functional Connectivity Density and FCS is short for Functional Connectivity Strength.

  • mask: could be whole brain mask or gray matter mask.
  • id index: identifier to find unique string for each subject
  • filetype: files in the filetype will be searched in input directories.
  • 4D nifti files: if the input data is 4D, check this item. Otherwise uncheck.
  • input dirs: directories can be input either using a .txt file or spm select window.
  • compute: use OPENCL supported CPU or GPU to calculate FCD
  • r threshold: threshold of correlation (to binarize functional connectivity and sum up)
  • metrics:
    1. fcd - functional connectivity density, calculate global and region grow defined degree
    2. fcs - functional connectivity strength, calculate global-wise sum/mean of above threshold intensity
    3. fcs abs - absolute functional connectivity strength, firstly convert FC map to absolute value and calculate global-wise sum/mean of above threshold intensity
  • out dir: output directory for saving results.
  • Buttons:
    • S: Save parameters of the current panel to a *.mat file. The *.mat can be further loaded for the panel or be used in a script processing.
    • L: Load parameters from *.mat for the current panel.
    • ?: Help information.
  • Output files:
    • Raw:
      • gfcd(global fcd): count the number of voxels of voxel to whole brain correlation (rho > threshold)
      • lfcd(local fcd): count the number of voxels of voxel to neighbour voxels’ correlation (rho > threshold, with region grow method)
      • lrfcd(long-range fcd): gfcd - lfcd
      • fcs_sum: sum of above threshold voxels’ intensity
      • fcs_ave: mean of above threshold voxels’ intensity
    • Normalized:
      • gfcd: gfcd(Raw) divided by mean value of gfcd(Raw)
      • lfcd: lfcd(Raw) divided by mean value of lfcd(Raw)
      • lrfcd: lrfcd(Raw) divided by mean value of lrfcd(Raw)
      • fcs_sum_nor: fcs_sum(Raw) divided by mean value of fcs_sum(Raw)
      • fcs_ave_nor: fcs_ave(Raw) divided by mean value of fcs_ave(Raw)
  • Reference:
    Tomasi, D., & Volkow, N. D. (2010). Functional connectivity density mapping. Proceedings of the National Academy of Sciences of the United States of America, 107(21), 9885-90.