Preterm babies may suffer memory and learning problems in their teen years, according to researchers at the University of Adelaide in Australia.
The study found reduced plasticity — the ability of the brain to reorganize neural pathways based on new experiences — in the brains of teenagers who were born at or before 37 weeks gestation.
“Plasticity in the brain is vital for learning and memory throughout life,” said Dr. Julia Pitcher of the University of Adelaide’s Robinson Institute.
“It enables the brain to reorganize itself, responding to changes in environment, behavior and stimuli by modifying the number and strength of connections between neurons and different brain areas. Plasticity is also important for recovery from brain damage.”
“We know from past research that preterm-born children often experience motor, cognitive and learning difficulties. The growth of the brain is rapid between 20 and 37 weeks gestation, and being born even mildly preterm appears to subtly but significantly alter brain microstructure, neural connectivity and neurochemistry,” she added.
“However, the mechanisms that link this altered brain physiology with behavioral outcomes — such as memory and learning problems—have remained unknown,” said Pitcher.
For the study, preterm teens were compared to those born full term, and also with full-term adults. Researchers used a non-invasive magnetic brain stimulation technique which induced responses from the brain to gain a measure of its plasticity.
Levels of cortisol, typically produced in response to stress, were also measured to gain a better understanding of the chemical and hormonal differences between the groups.
“Teenagers born preterm clearly showed reduced neuroplasticity in response to brain stimulation,” Pitcher said. “Surprisingly, even very modest preterm birth was associated with a reduced brain response. On the other hand, term-born teenagers were highly ‘plastic’ compared with adults and the preterm teens.”
Preterm teens had low levels of cortisol in their saliva, said Pitcher, which was highly predictive of reduced brain responsiveness.
“People often associate increased cortisol with stress, but cortisol fluctuates up and down normally over each 24-hour period and this plays a critical role in learning, the consolidation of new knowledge into memory and the later retrieval of those memories,” she said.
This factor could be important in the development of a potential new therapy for the neuroplasticity problem.
The results of the research are published in the Journal of Neuroscience.
Source: University of Adelaide