3D Fourier

  • Purpose: This command allows the user to apply a highpass and lowpass filter to the functional dataset.
  • Usage: 3dFourier can be used by putting the below command (or one similar to that) within an executable text

    file. The text file should be placed within the path or within the directory you'll be using. Values for the high and low pass filters are in Hz, and are typically calculated by using the following formula: 1)highpass filters are typically calculated by taking 1/(2xtriallength; 2)lowpass filters are typically calculated by taking 1/(something less than 6).

           3dFourier \
            -prefix my_filtered_fxnls \
            -lowpass .2 \
            -highpass .008 \
            mydataset+orig
  • The subcommand "-prefix" is used to specify the output file after filtering is complete.
  • The subcommand "-lowpass .2" tells 3dFourier that you want to eliminate anything within your data that has a frequency of .2 Hz or higher
  • "-highpass .008" tells 3dFourier to filter anything within your data that has a frequency of .008 or lower.
  • "mydataset+orig" is the input dataset you want filtered.