Hello,
I'm trying to perform ALFF/fALFF analyses at specific frequency subbands and am running into some problems. I'm able to create ALFF/fALFF maps at the .01-.1, .01-.08, and .073-.198 frequency bands but not at the .01-.027, .027-.073, .01-.073, and .198-.25 bands. The .01-.027 band returns only nan values while the other bands return only one value for the entire map (e.g. ALFF of 31.9095 for the .027-.073 band, 37.3064 for the .198-.25 band). The Temporal Dynamics 4d file shows changes across, but not within, timepoints. Any idea what the issue is? I'm using scans with a TR of .8 and 383 frames.
Thank you,
James
Forums
Seems you filted before ALFF
Seems you filted before ALFF/fALFF analysis?
This is static ALFF or dynamic ALFF?
This is static ALFF. I reran
This is static ALFF. I reran this on unprocessed resting state data and got the same issue so filtering doesn't seem to be the problem. The nans in the .001-.027 band may be due to the relatively short scan time but I'm not sure what would cause the value uniformity in the other bands.
Thank you,
James
I can not replicate this
I can not replicate this problem.
Could you show your settings, and show a time course of your data? DPABI->Viewer->More->Time Courses.
https://imgur.com/a/6lN2wlx
https://imgur.com/a/6lN2wlx
You are using 30 TR as a
You are using 30 TR as a window, and 0.8 as TR. Thus for each window it's 30*0.8=24s.
You can not get anything under 1/24=0.042 Hz, and probably higher.
Thank you, changing the
Thank you, changing the window size fixed the issue.