mfcsc -- Mismatch between Functional Connectivity and Structural Connectivity  
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 JOURNAL ARTICLE
 
      Civier O, Sourty M, Calamante F (2023) MFCSC: Novel method to calculate mismatch between functional and structural brain connectomes, 
      and its application for detecting hemispheric functional specialisations. Scientific Reports https://doi.org/10.1038/s41598-022-17213-z

 VERSION

      1.1

 USAGE

     From Neurodesk (no Matlab license required!):
         See https://osf.io/d7j9n/

     From Matlab IDE:
         1. Download the archive of the software from https://github.com/civier/mfcsc/releases/tag/1.1 and extracts it to a folder
         2. Start Matlab and change to the folder with the code
         3. Run the following command inside Matlab -
         mfcsc(FC_SC_LIST,FC_INPUT_DIR,SC_INPUT_DIR,OUTPUT_DIR,not_in_mask_value,is_contra,is_keep_neg_fc,is_symmetrical,is_figures,bct_dir)         

     From the command-line:
         1. Download the archive of the software from https://github.com/civier/mfcsc/releases/tag/1.1 and extracts it to a folder
         2. Open a terminal and change to the folder with the code
         3. Enter the following command at the terminal -
         matlab -batch "mfcsc(FC_SC_LIST,FC_INPUT_DIR,SC_INPUT_DIR,OUTPUT_DIR,not_in_mask_value,is_contra,is_keep_neg_fc,is_symmetrical,is_figures,bct_dor)"

     The 4 arguments in caps are mandatory. 

     IMPORTANT: before running mfcsc, it is recommended to open FC_SC_LIST 
     and visually check that the two columns have matching
     participant connectomes.

 PREREQUISITES:

     Neurodesktop 20230324 or newer 
     (older versions of Neurodesktop should work as well, but not tested; to use in older versions, load from the terminal using: 'ml mfcsc/1.1')

          OR

     Matlab 9.8.0.1721703 (R2020a) Update 7 or newer (older versions of Matlab should work as well, but not tested)
     Matlab's Curve Fitting toolbox

 DESCRIPTION

     mfcsc receive pairs of functional and structural connectivity
     matrices, one pair per participant. For each participant, mfsc
     calculates a connectivity matrix that gives the mFCSC metric
     value for every connection. 

     The mFCSC metric can be calculated either for ipsilateral or 
     contralateral connectionsis (but not both), and is ill-defined 
     for some connections. The 'mask.csv' binary matrix mask
     indicates which mFCSC metrics should be included in further analysis. 
     The cells that should not be consulted further are set to -99.

 INPUT

     The input connectivity matrices should be comma seperated values that describe symmetrical 
     connectomes (i.e., connections do not have directionality). 
     Only the upper right triangle of the connectivity matrices is
     consulated. This also excludes the main diagonal.

     The connectivity matrices must have an even number of regions N: regions numbers 
     1 to N/2 for one hemisphere, and regions number N/2+1 to N for the other.
     Note that the order of regions for each hemisphere may be different, i.e., 
     regions number i and N/2+i do not have to be homologous.

 OUTPUT

     IMPORTANT: before consulting the output, ensure that the file1 and file2 parts 
     of the filenames below represent matching connectivity
     matrices!
     
     The output of mfcsc consists of one connectome file for each participant:

             mFCSC-file1-file2-masked.csv - connectome of mFCSC values for the
                                            participant whose FC and SC
                                            connectomes are stored in file1 and file2
                                            respectively (excluding
                                            the files extensions)

     The main output of mfcsc consists of the file:

             mask-final.csv - final mask indicating the connections to which mFCSC is calculated



     There are also several misc files in the group_connectomes subdir:

         transformed_SC_avg - the average transfered SC connectome
         FC_avg - the average FC connectome
         mask-direct_SC_is_shortest_path.csv - mask of connections in which the path length of the direct connection (1/transformed_SC) is shorter than any other indirect path between the two regions
         SC_avg - the average SC connectome

 MANDATORY ARGUMENTS

     FC_SC_LIST (path)

     Path to a tab-separated file with two columns.
     The first column lists the files with the connectivity matrices of the FC connectomes
     The second column lists the connectivity matrix files for the matching SC connectomes

     An easy method to generate the FC_SC_LIST on Linux or MacOS is to:
     1) include a matching participant ID in the filenames of both FC and SC connectomes 
        (plus optional fixed prefixes and suffixes for each modality).
     2) put all FC connectomes in one folder and all SC connectomes in another,
        ensuring that there are no other files in these folders.
     3) change the working directory to the folder with FC connectomes, and run:
         ls | sort -n > /tmp/fc_list
     4) Change the working directory to the folder with the SC connectomes, and run:
         ls | sort -n > /tmp/sc_list
     5) Run:
         paste /tmp/fc_list /tmp/sc_list > path_to_filename
     6) Provide path_to_filename as the FC_SC_LIST argument

     FC_INPUT_DIR (path)

     The directory containing the files with the FC connectivity matrices

     SC_INPUT_DIR (path)

     The directory containing the files with the SC connectivity matrices

     OUPTUT_DIR (path)

     The output directory where the mask and mFCSC files are to be
     saved

 OPTIONAL ARGUMENTS

     not_in_mask_value (any number)

     Value that will be assigned to cells in the output matrices that are
     not in the mask. By deafult it is set to -99 to make sure
     people do not report the values in these cells.
     Can be set to 0 to prevent this value from affecting color scaling of plots.    

     is_contra (true or false)
     
     By default, mFCSC is calculated for ipsilateral connections
     (is_contra = false or omitted)
     set is_contra to true to calculate mFCSC for contralateral connections instead.

     is_keep_neg_fc (true or false)

     By default, mFCSC removes cells that have negative mean FC before 
     fitting the model used to transform SC
     (is_remove_negative_fc = false or omitted)
     set is_keep_negative_fc to true to keep them

     is_symmetrical (true or false)

     By default, only the upper right triangle of the output matrices is
     populated, with the lower triangle being zeroed out.
     (is_symmetrical = false or omitted)
     set is_symmetrical to true to save symmetrical matrices instead by
     mirroring the upper right triangle into the bottom left triangle
     In both cases, the main diagonal is zeroed out.

     is_figures (true or false)

     By default, do not show figures.
     (is_figures = false or omitted)
     set is_figures to true to print verbose figures with information for QC and debg.
     Not tested. Use at your own risk!

     bct_dir (path)

     If specified, Matlab will look for the Brain Connectome Toolbox (BCT)
     in this directory instead of the BCT version supplied with
     MFCSC (2017/01/15). BCT is required in order to calculate the mask.
     This argument is not available in the Neurodesk version, where only the supplied
     BCT can be used.

 NOTE
     
     Cells of individual SC connectivity matrices that have the value of 0 are
     not transfromed well using the model.
     In most cases these cells will not be included in the mask because the
     direct SC in the average SC connectome is not the shortest path;
     however, in case they are within the mask after all, a warning will
     be issued and they will be assigned the mFCSC value of -999.
     In this case, one approach is to manually exclude these cells from the
     mask by editing 'mask-final.csv' and using the ammended mask in
     further analyses.

  EXAMPLE

     For the processing performed in the journal article, see:
     https://osf.io/d7j9n/ under "TESTING MFCSC INSTALLATION"

  DEVELOPER

     Oren Civier ([email protected])
     https://www.swinburne.edu.au/research/our-research/access-our-research/find-a-researcher-or-supervisor/researcher-profile/?id=ocivier

  CITATIONS

     When using mfcsc, authors should cite:

         Civier O, Sourty M, Calamante F (2023) MFCSC: Novel method to calculate mismatch between functional and structural brain connectomes, 
         and its application for detecting hemispheric functional specialisations. Scientific Reports https://doi.org/10.1038/s41598-022-17213-z

         Rubinov M, Sporns O (2010) Complex network measures of brain connectivity: Uses and interpretations. NeuroImage 52:1059-69.%

  ACKNOWLEDGMENTS

     National Health and Medical Research Council of Australia (grant numbers APP1091593 andAPP1117724)
     Australian Research Council (grant number DP170101815)
     National Imaging Facility (NIF), a National Collaborative Research Infrastructure Strategy (NCRIS) capability at Swinburne Neuroimaging, 
     Swinburne University of Technology.