Submitted by xuercan on Sun, 04/17/2011 - 16:41
最近，一直用ICA处理静息态的数据，突然被人问及了一个这样的问题。确实不知道该怎么回答。
Since the global signal tends to affect the default network connectivity map, why did your NOT try to remove such global effect before the ICA analysis?
ICA的处理过程（如Grecious 2004,2007等）好像都没有提到或涉及到这个global signal，同时有关ICA的处理过程及原理的文章中（如colhoun 2001 A method for making group inferences from functional MRI data using independent component analysis 和colhoun 2009的 A review of group ICA for fMRI data and ICA for joint inference of imaging, genetic, and ERP data文章）都没有提到global signal这个问题，请问这个问题该怎么样回答呢？
Submitted by YAN Chao-Gan on Sun, 04/17/2011 - 22:15 Permalink
Re
个人理解：在做功能连接之前去除global signal，是传统上认为它与生理噪声有关。当然，关于这个问题最近还是有很多争议的，见Murphy, K., Birn, R.M., Handwerker, D.A., Jones, T.B., Bandettini, P.A., 2009. The impact of global signal regression on resting state correlations: are anti-correlated networks introduced? Neuroimage 44, 893-905.
而在ICA的研究中，常被认为ICA可以找到呼吸心跳等生理成份，如Beckmann et al., Investigations into resting-state connectivity using independent component analysis Philos Trans R Soc Lond B Biol Sci. 2005 May 29; 360(1457): 1001–1013.
如果是审稿意见的话，你也可以看一下这些相关的文献，然后在你的结果中看看能否找到相关的呼吸心跳成份，做个解释说不用做之前的去global signal了。
Submitted by YAN Chao-Gan on Sun, 04/17/2011 - 22:15 Permalink
Re
个人理解：在做功能连接之前去除global signal，是传统上认为它与生理噪声有关。当然，关于这个问题最近还是有很多争议的，见Murphy, K., Birn, R.M., Handwerker, D.A., Jones, T.B., Bandettini, P.A., 2009. The impact of global signal regression on resting state correlations: are anti-correlated networks introduced? Neuroimage 44, 893-905.
而在ICA的研究中，常被认为ICA可以找到呼吸心跳等生理成份，如Beckmann et al., Investigations into resting-state connectivity using independent component analysis Philos Trans R Soc Lond B Biol Sci. 2005 May 29; 360(1457): 1001–1013.
如果是审稿意见的话，你也可以看一下这些相关的文献，然后在你的结果中看看能否找到相关的呼吸心跳成份，做个解释说不用做之前的去global signal了。