correct for head motion

Submitted by fish on Wed, 06/17/2015 - 15:26

Dear Dr. Yan,


I am sorry to bother you that  if I correct head motion before using DPARSFA, will it affect the result of head motion? Because when I use two different ways, to be more precise, I use head motion correction before and after realignment, the results of exclude subjects according to max head motion are different. The result of  head motion correction before realignment manully is excluded according to DPARSFA, but raw data without  head motion correction is not. I would like to know does it make a big difference with two different ways, especially whether affect the final result? Because if we use spm for preprocessing, we will correct head motion in the first step.


I am looking forward to your replies!


Best


Fish

Forums:

YAN Chao-Gan

Wed, 06/17/2015 - 15:37

Hi Fish,

What do you mean "head motion correction before and after realignment"? Realignment is head motion correction. Or do you mean regress out head motion parameters?

Best,

Chao-Gan

silence

Wed, 06/17/2015 - 16:20

fish

Wed, 06/17/2015 - 17:59

Dear Dr.Yan,


I am sorry that I did't express myself clearly. 'Head motion correction' in my words means reorientation head to AC-PC lines, and I did the rest image and T1 image both.


Best


Fish

YAN Chao-Gan

Wed, 06/24/2015 - 01:03

Hi Fish,

Reorienting to AC-PC lines is not head motion correction. This does affect the realign parameters, because the realign parameters depend the origin. However, it should not affect framewise displacement. I think either before or after should be OK.

Best,

Chao-Gan

fish

Wed, 06/24/2015 - 14:04

Dear Dr.Yan,


Thanks for your answers!


Best


Fish