the global sigal impact on the resting state data during the independent component analysis

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?

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。

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。