Brain scans of premature babies show differences in the connections between key neural regions, which could heighten the risk of developmental disorders, new research suggests.
Previous research has shown that babies born prematurely are more susceptible to certain childhood psychiatric disorders, including conditions such autism and attention deficit hyperactivity disorder.
The results of this latest study could help researchers understand why they're more vulnerable to these conditions than infants born at term, and could help them identify treatments or medications that might encourage normal development.
"The ability of modern science to image the connections in the brain would have been inconceivable just a few years ago, but we are now able to observe brain development in babies as they grow, and this is likely to produce remarkable benefits for medicine," neonatal paediatrician David Edwards, from King's College London (KCL) in the UK, said in a press release.
The researchers took MRI scans of the brains of 66 infants - 47 of which had been born prematurely before the 33-week mark. The other 19 had been born during the normal birth window, at between 37 and 42 weeks.
The team looked specifically at the neural connections between the thalamus, which relays sensory information to other parts of the brain, and the cerebral cortex, which plays an important role functions like memory, attention, language and consciousness.
These connections develop rapidly during the final stages of pregnancy, but for babies born prematurely, this development occurs in a dramatically different environment: the neonatal unit rather than the womb.
"In the womb, there is perfect nutrition delivered into the baby's bloodstream, regulation of temperature, and protection against infection delivered from the mother in the last trimester," lead author Hilary Toulmin, from KCL, told The Guardian. "So there are many influences before they have their MRI scan."
The researchers found that children born in the normal window of birth showed a remarkably similar structure to adults in these brain regions, which supports existing evidence that our brain's neural connectivity is quite mature at birth.
But the MRI scans also revealed some key irregularities between the brains of premature and healthy infants. Most notably, the premature infants had less connectivity between areas of the thalamus and areas of the cortex known to support higher cognitive functions.
"In studies of adolescents and adults, these areas form the salience network, and that network is found to be disrupted in conditions such as ADHD and autism. Premature infants are at greater risk of both of these," Toulmin told The Guardian.
Interestingly, the MRI scans also revealed that the premature babies had increased neural connectivity between the thalamus and the primary sensory cortex - an area of the brain that processes signals from the face, mouth, jaw, lips, tongue and throat. The researchers suspect that this increased connectivity reflects their early exposure to breast and bottle-feeding.
The team's findings were published in the Proceedings of the National Academy of Sciences.
"The next stage of our work will be to understand how these findings relate to the learning, concentration and social difficulties which many of these children experience as they grow older," Toulmin said in the release.