Fair et al. (Fair et al., 2008) examined functional connectivity between 13 published ROIs from the DMN over development in healthy subjects 7–30 years old. Here, ROIs were modeled as 10 mm diameter spheres, and functional connections were measured by Pearson correlations between ROI timecourses. A principal finding of this study is shown in Figure 2. At a chosen threshold (r > 0.15), networks in children ages 7–9 years existed in 5 unconnected pieces (Figure 2A), whereas in young adults 21–31 years old the networks formed an integrated DMN (Figure 2B). Nearly all developmental changes in correlation strengths among these ROIs were increases (see Figure 2C insets, far right), and increases largely occurred in an anterior-posterior orientation (Figure 2C). One interesting point to note is that the sole long-distance anterior-posterior correlations present in children linked medial prefrontal cortex (MPFC) and superior frontal nodes to lateral parietal and posterior cingulate (PCC) and retrosplenial nodes (Figure 2A). This result was mirrored in MPFC seed correlation maps that showed only sparse correlations to the PCC, superior frontal, lateral parietal, and lateral temporal cortex
