fALFF的文章写作中的问题

Submitted by Feng Dan on

严老师:

您好!最近有一篇文章返回来大修,审稿人对于fALFF提出了一个问题,由于自己可能对这个问题理解的不太深入,不知道怎么回答比较好,所以需要您的帮助。

问题如下:

What is the point of band pass filtering to reduce drift and cardiac/respiratory noise AFTER you've calculated fALFF? Shouldn't dealing with drift and physiologic noise be done prior to calculating fALFF?

 

对于fALFF的方法描述中,我是这样写的:“After above preprocessing, fALFF was calculated by the REST v 1.8 software (http://restfmri.net/forum/REST_V1.8) (Song et al. 2011). First, the time series for each voxel were transformed with a Fast Fourier Transform (FFT) to obtain the power spectrum. Then, the square root was calculated at each frequency of the power spectrum, and the averaged square root was acquired as ALFF across 0.01–0.08 Hz at each voxel. Next, fALFF was calculated using the ratio of power spectrum of low-frequency (0.01 Hz to 0.08Hz) to that of the entire frequency range. Finally, the fMRI data were temporally band pass filtered (0.01 Hz to 0.08Hz) to reduce low frequency drift and high frequency respiratory and cardiac noise.”我不知道我这样写是不是准确的。

谢谢!

YAN Chao-Gan

Tue, 06/02/2015 - 02:52

你好!

你的描述有误。最后一句”Finally, the fMRI data were temporally band pass filtered (0.01 Hz to 0.08Hz) to reduce low frequency drift and high frequency respiratory and cardiac noise.“应删去,计算fALFF没有这一步操作。

超赣

严老师:

您好!谢谢您的回复,那我是不是应该把最后一句当中的“the fMRI data”改为“the fALFF data”就是正确的。

还想麻烦的是,我个人觉的reviewer的意见好像重点在于为什么不在计算fALFF之前进行滤波,而是在之后进行,在之后进行又有什么意义。这个我不太能hold住,所以需要您的帮助,谢谢您啦。