Brain scans of children who were born prematurely have revealed differences in the connectivity of key regions that may play a role in developmental disorders, including autism.

Scientists from the Centre for the Developing Brain at King’s College London used functional magnetic resonance imaging (fMRI) scans to map the brain connections of 66 infants, 47 of whom were born prematurely before 33 weeks of pregnancy.

Babies born in the “normal” birth window of 37 to 42 weeks gestation had a similar brain structure to adults in key areas known to develop rapidly during the time a pre-term infant is cared for in a neonatal unit.

But those born early had less connectivity between parts of the thalamus and specific regions of the brain’s cortex that support higher mental functions.

At the same time, they had more connectivity between the thalamus and an area of the primary sensory cortex involved in processing signals from the face, lips, jaw tongue and throat.

Other parts of the brain were the same between the two groups of infants.

“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,” Hilary Toulmin, a clinical research fellow at King’s said.

“In the case of ADHD, it is particularly inattention which is associated with preterm birth. They are not hyperactive, but have poor concentration and perhaps therefore go unnoticed more easily.”

All of the information we receive from the outside world, including vision, sound and touch, passes through the thalamus and onwards to specific parts of the cortex for processing. The sight of a car, for example, will pass from the eyes and retina to the thalamus and then to the visual cortex.

“The areas affected in the premature infants are the areas of the thalamus which are connected to many areas of the cortex,” added Ms Toulmin, whose study appears in Proceedings of the National Academy of Sciences.

“There are enormous differences between being in the womb and being in a neonatal unit. As parents of preterm infants know very well, first learning to breathe unassisted, then learning to breast or bottle feed so that they don’t have to be fed milk through a tube, and be able to maintain their body temperature without an incubator to help, are among the first challenges.

“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. So there are many influences before they have their MRI scan.”