Modulatory interactions between the default mode network and task positive networks in resting-state.

Xin Di,Bharat B Biswal

doi:10.7717/peerj.367

Abstract

The two major brain networks, i.e., the default mode network (DMN) and the task positive network, typically reveal negative and variable connectivity in resting-state. In the present study, we examined whether the connectivity between the DMN and different components of the task positive network were modulated by other brain regions by using physiophysiological interaction (PPI) on resting-state functional magnetic resonance imaging data. Spatial independent component analysis was first conducted to identify components that represented networks of interest, including the anterior and posterior DMNs, salience, dorsal attention, left and right executive networks. PPI analysis was conducted between pairs of these networks to identify networks or regions that showed modulatory interactions with the two networks. Both network-wise and voxel-wise analyses revealed reciprocal positive modulatory interactions between the DMN, salience, and executive networks. Together with the anatomical properties of the salience network regions, the results suggest that the salience network may modulate the relationship between the DMN and executive networks. In addition, voxel-wise analysis demonstrated that the basal ganglia and thalamus positively interacted with the salience network and the dorsal attention network, and negatively interacted with the salience network and the DMN. The results demonstrated complex modulatory interactions among the DMNs and task positive networks in resting-state, and suggested that communications between these networks may be modulated by some critical brain structures such as the salience network, basal ganglia, and thalamus.

Highlights

The human brain is intrinsically organized as different networks as generally revealed by resting-state functional magnetic resonance imaging (Beckmann et al, 2005; Golland et al, 2008; Yeo et al, 2011)
The salience network revealed a positive correlation with the dorsal attention network (MFisher’s z = 0.333), but a negative correlation with the right executive network (MFisher’s z = −0.142)
The posterior default mode network (DMN) revealed a negative correlation with the salience network (MFisher’s z = −0.251), while positive correlations with the left executive network (MFisher’s z = 0.320) and the right executive network (MFisher’s z = 0.188)

Summary

Introduction

The human brain is intrinsically organized as different networks as generally revealed by resting-state functional magnetic resonance imaging (fMRI) (Beckmann et al, 2005; Golland et al, 2008; Yeo et al, 2011). Brain regions that belonged to different networks generally have weaker connectivity, How to cite this article Di and Biswal (2014), Modulatory interactions between the default mode network and task positive networks in resting-state. There are two major systems in the brain; the task positive network shows consistent activations across different tasks (Shulman et al, 1997a), while the default mode network (DMN) shows consistent deactivations (Shulman et al, 1997b). These two systems reveal moment to moment anticorrelation even when the subject isn’t performing explicit tasks (Fox et al, 2005). The controversies of negative correlation may partially due to the fact that the connectivity between the DMN and the task positive network are highly variable (Chang & Glover, 2010; Kang et al, 2011)

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