Where is the grey matter signal in DPARSF

Submitted by haohaoxuexi on Fri, 11/16/2012 - 05:34

 Hello, everybody,
I have heard that there is grey matter signal in DPARSF result, but I don't know the location. How to get them? Who knows. Please tell me. It is not easy to understand even the most fundamental concept.
Thank you very much!
Xuemin

Submitted by haohaoxuexi on Fri, 11/16/2012 - 12:48

Hi, Teacher Zang,
  I learnt from the video course that when we compare AD and NC , we can use the "grey matter signal" as an image covariates to exclude the  influence of the structural atrophy. Then it said there is " grey matter signal" in the DPARSF results. We can obtain from DPARSF processing, but have to reslice to 3*3*3 since the different accuracy . Therefore, how can I get the "grey matter signal".
Am I understood?

Thank you so much for your time. Forgive my hard English. I am working on it.
xuemin

Submitted by YAN Chao-Gan on Sat, 11/17/2012 - 00:06

Hi,

It's "grey matter density" other than "grey matter signal".

Please find the "wc1*" files within "sub00X" under "T1ImgNewSegment" or "T1ImgSegment". These are the grey matter density files which can be used as covariates.

Best,

Chao-Gan

Submitted by haohaoxuexi on Sat, 11/17/2012 - 01:25

THANK YOU !
I can't fide the file. Firstly, I thought the file obtained from the "Functional Connectivity" part, global mean -CSF -white matter. But they are "signals".Then I conclude that ,to obtain the "grey matter density", I need to use " T1 image unified segmentation". I used EPI templates, therefore I do not have the files. I shoude arrange my "T1" data. Do I have to repreprocess my data? 
I really appreciate your help. 
Xue

Submitted by YAN Chao-Gan on Wed, 11/21/2012 - 02:43

 Hi!

What do you want to do?

The global/WM/CSF signal regression in functional connectivity analysis is another thing.

If you want to use grey matter density as a covariate in group analysis, you may need to check "segment" or "new segment".

Best,

Chao-Gan

Submitted by wuqinjuan1 on Sat, 12/01/2012 - 18:44

严超赣老师您好！我们用的是EPI模板，没用T1像做模版，所以没生成wc1文件，那么在做功能连接去除协变量时，是不是灰质体积的影响就不能被去除了呢？谢谢！

Submitted by YAN Chao-Gan on Sun, 12/02/2012 - 01:48

你好！

上面讨论的不是这个问题。上面讨论的是采用灰质密度做为组分析的协变量。

在做功能连接去除协变量的时候，通常是不会去除灰质信号的（虽然所谓全脑信号大部分是来源于灰质）。全脑信号的MASK是来源于先验MASK，没有T1像也没有影响的。