London, May 5 (IANS): Premature birth can alter the connectivity between key areas of the brain, thereby making them vulnerable to disorders such as autism, says a study.

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

"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," said first author of the study Hilary Toulmin, from King's College London.

The researchers 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 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 study was published in the journal PNAS -- Proceedings of the National Academy of Sciences.