How does preterm birth affect newborn brain networks?
Preterm birth disrupts the development of functional brain networks at normal term age, causing widespread reductions in network strength alongside an abnormal increase in specific movement-related connections.
Source
The Developing Human Connectome Project: typical and disrupted perinatal functional connectivity
What they did
Researchers used resting-state functional MRI to map brain connectivity in a sample of 337 newborn infants. A sub-sample of 24 healthy, full-term infants was scanned late to define 11 typical resting-state networks. The researchers then analyzed and compared these networks in 248 full-term infants and 65 preterm infants scanned between normal birth-equivalent ages.
What they found
Full-term infants showed a clear development pattern where primary sensory and motor networks were already mature, while complex thinking networks were still fragmented and maturing. In contrast, preterm infants scanned at their expected birth age showed a 23-41% reduction in overall brain network strength across all networks compared to full-term infants. However, preterm infants also exhibited an abnormal increase in connectivity in a brain region involved in coordinating physical movements.
The limits
What it doesn't show
While the study shows clear differences in connectivity patterns, it cannot prove that preterm birth directly causes these changes, nor does it link these brain differences to actual behavioral or cognitive problems later in life. Additionally, because the brain scans were taken at a single point in time for each infant rather than tracking the same babies longitudinally, the developmental trajectories are inferred rather than observed directly. Finally, the imaging techniques used are less sensitive to deeper brain regions, meaning potential disruptions in subcortical areas like the thalamus might be missed.
Key terms
- Postmenstrual age (PMA)
- The time elapsed between the first day of the last menstrual period and birth, plus the time elapsed after birth.
- Resting-state functional MRI (rs-fMRI)
- A neuroimaging technique used to evaluate regional interactions in the brain when a subject is not performing an explicit task.
- Resting-state networks (RSNs)
- Patterns of synchronized, low-frequency brain activity that naturally occur across different regions of the brain while at rest.
- Independent component analysis (ICA)
- A mathematical method that separates a mixed, complex signal into distinct, independent sub-components to identify structured brain networks.
- Default-mode network (DMN)
- A network of interacting brain regions that is typically active when a person is not focused on the outside world.
- Core network strength
- A measure used in this study to quantify the overall signal coordination and integrity within a specific brain network.
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Quiz yourself
At what postmenstrual age (PMA) can immature resting-state networks (RSNs) first be identified in preterm infants?
Common questions
Why did the researchers study sleeping babies without any active tasks?
Testing infants during active tasks is extremely difficult because they cannot follow instructions; resting-state scans during natural sleep allow researchers to measure intrinsic brain activity and map complex networks without requiring any effort from the baby.
What is the difference between primary networks and association networks?
Primary networks handle basic sensory and motor functions like seeing, hearing, and moving, whereas association networks integrate this basic information to support more complex, higher-order cognitive tasks.
Does this mean all preterm babies will experience developmental issues?
No, the study identifies group-level differences in brain wiring rather than predicting individual outcomes, and future longitudinal studies are needed to determine if these specific connectivity patterns correlate with real-world cognitive or motor challenges.
Why might preterm babies show increased connectivity in the motor network?
Being born early exposes the infant's highly plastic sensory and motor systems to the outside world earlier than normal, which may unnaturally accelerate or alter the wiring of connections that coordinate movement and physical feedback.
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