Immature default mode network in young children: Evidence from combined resting state fMRI and diffusion tensor imaging analysis

https://doi.org/10.1016/S1053-8119(09)70593-2Get rights and content

Introduction

The default-mode network (DMN) is a set of brain regions with the unique property of exhibiting deactivation during cognitively demanding externally-oriented tasks, and paradoxically high levels of activity during “task-free” (resting) conditions (Greicius et al., 2004, Raichle et al., 2007). While properties of this network have been well-documented in the recent cognitive neuroscience literature, its developmental trajectory in terms of both structure and function is still unclear. In this study, we examined developmental changes in the structural connectivity measured using quantitative diffusion tensor imaging (DTI) fiber tracking and functional connectivity measured using resting-state functional correlations between two key nodes of the DMN – the posterior cingulate cortex (PCC) and medial prefrontal cortex (MPFC).

Section snippets

Methods

We obtained resting-state functional magnetic resonance imaging (fMRI) and DTI data from 23 children (ages 7-9) and 22 IQ-matched young-adults (ages 19-22). The DMN was identified in fMRI data using group independent component analysis. The level of functional connectivity between the DMN regions was assessed by measuring the correlations between PCC and MPFC, controlling for the influence of other regions of the DMN.

DTI fiber tractography was used to estimate the anatomical connections between

Results

Replicating previous studies that have shown age-related increases in the functional connectivity between the anterior and posterior regions of this network, we found significantly higher levels of PCC-MPFC connectivity in young-adults compared to children (Figure 1). Young-adults also showed increased structural connectivity between the PCC and MPFC compared to children (Figure 2). Lastly, there was a significant correlation between structural and functional connectivity within the DMN in the

Conclusions

Although the default mode network can be consistently detected in 7-9 year old children, it is characterized by weaker and immature functional and structural connectivity between the PCC and the MPFC. Our findings are likely to be important for understanding the development of higher brain functions subserved by this important canonical brain network.

References (0)

Cited by (0)

View full text