Global and structured waves of rs-fMRI signal identified as putative propagation of spontaneous neural activity.

Neuroimage. 2016 Mar 21;

Authors: Amemiya S, Takao H, Hanaoka S, Ohtomo K

Abstract
Conventional resting-state fMRI (rs-fMRI) studies have focused on investigating the synchronous neural activity in functionally relevant distant regions that are termed as resting-state networks. On the other hand, less is known about the spatiotemporal dynamics of the spontaneous activity of the brain. By examining the characteristics of both rs-fMRI and vascular time lag that was measured using dynamic susceptibility contrast-enhanced perfusion weighted imaging, the present study identifies several structured propagation of the rs-fMRI signal as putative neural streams. Temporal shift of both rs-fMRI and perfusion imaging data in each voxel compared with the averaged whole brain signal was computed using cross correlation analysis. In contrast to the uniformity of the vascular time lag across subjects, whole brain rs-fMRI time lag was estimated to be composed of three independent components. After regression of vascular time lag, independent component analysis was applied to rs-fMRI data. The putative neural streams showed slow propagation of the signal from task positive regions to main nodes of the default mode network, which may represent a mode of transmission underlying the interactions among the resting-state networks.

PMID: 27012499 [PubMed - as supplied by publisher]