Dear Dr. Yan,
Have any studies examined the relations betweeen ALFF, ReHo and fALFF?
In my studies, the ReHo of LIFG were negatively associated with task effect of inferior LIFG, while the ALFF of LIFG was positively associated with task effect of superior LIFG. So I am interesting in the relations among these three indices.
thanks.
Daiqing
2015.12.10
Forums
Hi daiqing,
Hi daiqing,
I am also quite interested in your question. I think ALFF and Reho are two aspects of resting-state time series. By definition, ALFF measures the brain signal variability of a given voxel in the frequency domain. The Reho measures the "similarity" of a given voxel to its neighborhood voxels in the time domain. I am not surprised that you found different task correlations when using these measures. I assumed that the "task effect" you mentioned is the beta value obtained by a GLM. The positive correlation between ALFF and task effect may probably mean: the subject who has high "regional activity" in LIFG at rest shows more LIFG engaement when performing a task.
I think this paper may help you:
Regional homogeneity of resting-state fMRI contributes to both neurovascular and task activation variations
http://www.ncbi.nlm.nih.gov/pubmed/23969197
best,
zhizhou
Hi Daiqing and Zhizhou,
Hi Daiqing and Zhizhou,
The relationship between ALFF and ReHo is an interesting quesiton. ALFF is strongly coupled with fALFF (Zou et al., 2008; Zuo et al., 2010), and also positively correlated with ReHo across voxels (Nugent et al., 2015; Yuan et al., 2013). Across subjects, negative correlation between ALFF and ReHo was reported in parietal regions in stroke patients (Zhu et al., 2015).
Thus, you can try to measure the relationship between ALFF and ReHo in your data directly.
Best,
Chao-Gan
Nugent, A.C., Martinez, A., D'Alfonso, A., Zarate, C.A., Theodore, W.H., 2015. The relationship between glucose metabolism, resting-state fMRI BOLD signal, and GABAA-binding potential: a preliminary study in healthy subjects and those with temporal lobe epilepsy. J Cereb Blood Flow Metab 35, 583-591.
Yuan, R., Di, X., Kim, E.H., Barik, S., Rypma, B., Biswal, B.B., 2013. Regional homogeneity of resting-state fMRI contributes to both neurovascular and task activation variations. Magn Reson Imaging 31, 1492-1500.
Zhu, J., Jin, Y., Wang, K., Zhou, Y., Feng, Y., Yu, M., Jin, X., 2015. Frequency-dependent changes in the regional amplitude and synchronization of resting-state functional MRI in stroke. PLoS ONE 10, e0123850.
Zou, Q.H., Zhu, C.Z., Yang, Y., Zuo, X.N., Long, X.Y., Cao, Q.J., Wang, Y.F., Zang, Y.F., 2008. An improved approach to detection of amplitude of low-frequency fluctuation (ALFF) for resting-state fMRI: fractional ALFF. J Neurosci Methods 172, 137-141.
Zuo, X.N., Di Martino, A., Kelly, C., Shehzad, Z.E., Gee, D.G., Klein, D.F., Castellanos, F.X., Biswal, B.B., Milham, M.P., 2010. The oscillating brain: Complex and reliable. Neuroimage 49, 1432-1445.