ALFF analysis

Dear all,

I am very new to the Rest toolbox and have two questions regarding the ALFF analysis with Rest.

1. I am wondering why it appears as if my brain input is "distorted" after the bandpass filtering step or when I exclude the filtering, after the ALFF step? I attached pitcure: the first image is the preprocessed file, the seconds the detrended file, the third the detrended & filtered file and the fourth the ALFF_map. And as the blue haircross shows, a few milimeters have "disappeared" from the brain mask with the filtering step and in the ALFF_map compared to the original and detrended file. Am I doing something wrong or is this distortion "normal" and caused by the filtering? 

2. I am trying to script the analysis without the GUI. So far, I only receive the ALFF_map as output with the alff.m function. However, I would also like to generate the mALFF_map with my script and was wondering whether there is another function for it or if I will need to script this step? 

Thanks so much in advance for any help.

Best, Lena

Image icon distortion_001.jpg86.81 KB

Hi Lena,

   1) You don't need to bandpass filter before ALFF claculation.

   2)You can use script or RESTplus to calculate mALFF.

alff(AllVolume,ASamplePeriod, HighCutoff, LowCutoff, AMaskFilename, AResultFilename)