startup options

jip-glm (aka glm) is designed as a unix/linux program that requires that all necessary files are specified on the unix line at startup.  The general syntax is


glm  [GLM control file]  [options]


This program has few startup options.  The main option is "-p", which specifies that all signal-change files should use units of percent change by dividing the absolute signal changes, which are determined in GLM, by the DC component of the polynomial baseline description.

glm  glm.dat -p

This option is typical for BOLD or IRON fMRI, but it does not necessarily apply to ASL or to cases where the time series already has been converted to something other than signal (e.g., CBF, CBV, ...).


Other input options

-v or -V        Use verbose output.


-d [divisor]   Divide signal changes by divisor for output files.


-s                 Use very small memory allocation.  This generally isn't needed, as allocation already is

                    limited by default.  The program reads all input files in small bytes by reading a full time

                    series for a limited number of voxels each time.


Output files

For each condition specified in the GLM control file, there will be 3 output files:

  1. P-value maps                      P-condition.nii               e.g., P-LR.nii
  2. T statistic maps                   T-condition.nii               e.g., T-LR.nii
  3. Signal change maps            S-condition.nii               e.g., S-LR.nii
Joseph B. Mandeville, Athinoula A. Martinos Center for Biomedical Imaging at MGH/MIT/Harvard