Premature birth alters brain connections

Premature birth can alter the connectivity between key areas of the brain, according to a new study led by King's College London.

The findings should help researchers to better understand why premature birth is linked to a greater risk of neurod-developmental problems, including autistic spectrum disorders and attention deficit disorders.  

The  National Institute for Health Research-funded study, published in the journal PNAS, used functional magnetic resonance imaging (fMRI) to look at specific connections in the brains of 66 infants, 47 of whom were born before 33 weeks and were therefore at high risk of neurological impairment, and 19 born at term.

The brain connections investigated were between the thalamus and the cortex, connections which develop rapidly during the period a preterm infant is cared for on a neonatal unit. 

Researchers found that those born in the normal window of birth (37-42 weeks) showed a remarkably similar structure to adults in these brain regions, strengthening existing evidence that the brain's network of connections is quite mature at the time of birth.

However, infants born prematurely (before 33 weeks gestation) were found to have less connectivity between areas of the thalamus and particular areas of the brain's cortex known to support higher cognitive functions, but greater connectivity between the thalamus and an area of primary sensory cortex which is involved in processing signals from the face, lips, jaw, tongue, and throat. 

The greater the extent of prematurity, the more marked were the differences in the pattern of brain connectivity.

The authors suggest that the stronger connections involving face and lips in babies born preterm may reflect their early exposure to breastfeeding and bottle-feeding, while the reduced connectivity in other brain regions may be linked to the higher incidence of difficulties seen in later childhood.

Dr Hilary Toulmin, first author from the Centre for the Developing Brain at King's College London, says, "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."

According to Professor David Edwards, senior author from the Centre for the Developing Brain at King's College London, "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."