Group comparison, ROI analysis and smoothing

Submitted by David on Fri, 02/20/2015 - 18:23

Hi @all,

I have a question regarding the smoothing of RS fMRI data. I want to compare patiens and controls based on ALFF, fALFF,  ReHO, VHMC and also want to use the extracted AAL ROIs to analyze each subject individually for calculating cross-correlation between ROIs. Now I was wondering if it is even necessary to apply smoothing to the data at all? I was also wondering if it is necessary to apply the head motion scrubbing regressors or if ths will corrupt the calculation of ALFF, fALL asf. ? Because as I understood scrubbing removes bad time points.

Can anyone help me out here?

greetings

David

Forums:

YAN Chao-Gan

Sat, 02/21/2015 - 15:08

Hi David,

For ReHo, smoothing in preprocessing should not be performed. For the others, you can smooth in preprocessing or after the derivatives were generated.

I don't recommend scrubbing for ALFF/fALFF analyses. For the others, supplementary analysis with scrubbing can be performed to confirm the main results.

Best,

Chao-Gan

David

Sat, 02/21/2015 - 16:09

Thank you :). Is the scrubbing option in DPARSF the same as including the head motion scrubbing regressors? In other words, should I use neither of those options for ALFF/fALFF or can I use the head motion scrubbing regressors -option instead of the scrubbing option to get better data?

liuchen

Sun, 02/22/2015 - 04:09

？

------------------ 原始邮件 ------------------
发件人: "The R-fMRI Network"<rfmri.org@gmail.com>;
发送时间: 2015年2月22日(星期天) 凌晨0:09
收件人: "rfmri.org"<rfmri.org@rnet.co>;
主题: Re: [RFMRI] Group comparison, ROI analysis and smoothing





[To post a comment, please reply to rfmri.org@gm

YAN Chao-Gan

Sun, 02/22/2015 - 18:59

Hi David,

Scrubbing regressors are spike regression -> model the bad points in a regression model.


The second scrubbing is simply delete the bad points.

I will suggest the first option.

Best,

Chao-Gan


David

Tue, 02/24/2015 - 11:08

Thank you :)