A Case for Correcting Attenuation of Correlation in Resting State FMRI

Jacco A. De Zwart¹, Peter van Gelderen¹, Jeff H. Duyn¹

In low-noise situations the correlation between two signals is underestimated, an effect known as attenuation of correlation. This work shows that this well-established effect can lead to significant underestimation of cross-correlation in resting-state fMRI, where often the ratio between the neurogenic fluctuation of interest and noise level is less than 10. Correction of the cross-correlation value for this effect is well established and straightforward if the noise level is known.