Fig 1.
Summary of Tractography Methods.
Probabilistic tractography comparison between groups was performed as summarized above [33, 87, 88].
Fig 2.
Posteromedial Cortex Connectivity Comparison of Late Preterms versus Term Control Children.
Representative plots on standard anatomic images demonstrate increases in functional connectivity in late preterms within the posterior DMN components. There is significant decreased connectivity to components of the executive network (right frontal). These findings are consistent with late prematurity-related posterior DMN hyperconnectivity and increased anti-correlation (decreased functional connectivity) to the central-executive network.
Fig 3.
Subdivision of PMC functional connectivity into precuneus and posterior cingulate components.
RS-fMRI analysis of the PMC demonstrates increased connectivity in the posterior default mode network for PMC and its components. Anti-correlation with the salience and central-executive networks was only observed with the posterior cingulate seed and not when seeding the precuneus, however.
Fig 4.
Laterality of functional connectivity patterns of the posteromedial cortex.
Increased functional connectivity is demonstrated for both left (A) and right (B) PMC seeds within the posterior DMN with greater connectivity for the right hemispheric seeds. Decreased connectivity (increased anti-correlation) is seen within the central executive network.
Fig 5.
Lateral Parietal Cortex Connectivity Comparison of Late Preterms versus Term Control Children.
Increased connectivity within late preterm children is present predominantly within the posterior DMN when seeded from the angular and superior marginal gyri, although some increased connectivity was observed within the anterior cingulate cortex of the DMN. Decreased connectivity was observed within components of the salience network (insular cortex) and central executive network (prefrontal).
Fig 6.
Increased Structural Connectivity related to the Posteromedial Cortex within IFOF and ILF.
Using probabilistic tractography from the right PMC seed, increased streamlines were demonstrated within the right inferior longitudinal (occipitotemporal) fasciculus (ILF) and overlapping inferior fronto-occipital fasciculus (IFOF). These increased streamlines overlapped with the axon-rich sagittal stratum. Color bars indicate increased streamlines (+2.1 to +4.1) and decreased streamlines (-2.1 to -4.1).
Fig 7.
Comparison of Tractography Differences between the Right and Left Posteromedial Cortex.
Seeding from both the right and left posteromedial cortex demonstrated increased streamlines within the right ILF/IFOF, but the magnitude of increased streamlines was greater for the right PMC seed. Decreases within the splenium (mostly within the more right aspect) were seen with left seeding while at the same time significant increases were seen within subcortical white matter near the right lateral parietal cortex. Right seeding also showed decreases within the left posterior parietal subcortical white matter. Color bars indicate increased streamlines (+2.1 to +4.1) and decreased streamlines (-2.1 to -4.1).
Fig 8.
Lateral Parietal Cortex Structural Connectivity.
Anatomic-based seeding from the lateral parietal cortex (superior marginal and angular gyri) demonstrates decreased streamlines involving the splenium of the corpus callosum and increased streamlines within the frontal white matter near the supplementary motor area. Color bars indicate increased streamlines (+2.1 to +4.1) and decreased streamlines (-2.1 to -4.1).