Smooth is kind of average of one voxel and its nearby neighbors. If a voxel has some nearby neighbors which has very different value, after smooth the value on this voxel will changed, thus changed the result probably.
Different FWHM define different size of the area to be averaged. Although which is the best FWHM is very difficult to decide, I guess if the area you interested located near boundaries of different tissues, you'd better to not use large FWHM.
Thank you for the quick answer.I compare the MCI group with the control group,but the result is opposite with previous study.I have checked every step,no mistakes is found.Could this be possible?I tried falff,too.And the result is opposite with the result using alff.Can you tell me what I should do?I'll appreciate your answer very much.
Sorry for not familiar with MCI. You can wait for other one who can answer you about this.
But I suggest to make clear that previous study is in ReHo, ALFF or functional connectivity.
Different measurement reflect different things so it may be "opposite".
If exactly same things (including reprocessing steps, subject's age, gender, race and so on) in your results are opposite with previous ones, the possible explain is that fMRI signal of this disease may have a very unstable behavior cross different subjects.
But you need to check all the steps and all subject's status very carefully.
It's kind of you to answer my question so patiently.You've already help me a lot about smooth.As for the problem of MCI,I'll turn to another teacher.Thank you very much.
Smooth is kind of average of
Different FWHM define different size of the area to be averaged. Although which is the best FWHM is very difficult to decide, I guess if the area you interested located near boundaries of different tissues, you'd better to not use large FWHM.
Thank you for the quick
Sorry for not familiar with
But I suggest to make clear that previous study is in ReHo, ALFF or functional connectivity.
Different measurement reflect different things so it may be "opposite".
If exactly same things (including reprocessing steps, subject's age, gender, race and so on) in your results are opposite with previous ones, the possible explain is that fMRI signal of this disease may have a very unstable behavior cross different subjects.
But you need to check all the steps and all subject's status very carefully.
It's kind of you to answer my
空间平滑改变组间比较的结果
peak点坐标（-5，-48,27），差不多就是在23区。