Babies who weigh less than 1,500 grams at birth have their brain development affected, according to the results of a study published in the medical journal NeuroImage. Every year, one in ten babies worldwide is born prematurely. When children are born too young, they are at higher risk of physical and mental disabilities.
Researchers at the Norwegian University of Science and Technology (NTNU), conducted a study to better understand the consequences of very low birth weight on cognitive development.
To investigate this question, the researchers relied on a group of very low birth weight individuals born between 1986 and 1988 in Trondheim, Norway. These people had already participated in studies when they were 1, 5, 14 and 20 years old. Thirty-two people between the ages of 22 and 24 from this group participated in the new study and were matched with controls of the same age who were of normal birth weight.
For the first time, researchers used fMRI imaging (functional imaging) to see activation in different parts of the brain when subjects were engaged in a task.
In this study, participants looked at a computer screen and saw a series of random letters. Their task was to press a button as quickly as possible when they saw a new letter appear, except when the letter was ‘x’. The most common response was to press the button, as the letter “x” was presented only 10% of the time.
“You need two types of cognitive control to accomplish this task,” said Alexander Olsen, associate professor at the Norwegian University of Science and Technology (NTNU). “So this simple task gave us a lot of information.”
The brain is constantly working to create meaning from the flood of information that comes to us every minute of our day. The researchers identified two different processes that the brain relies on to accomplish this task: a proactive cognitive control function and a reactive function.
Proactive cognitive control is working proactively on a task. The participants knew that most of the time they had to press the button, and they mentally prepared themselves, proactively, to identify new letters to answer as quickly and as accurately as possible.
But the appearance of the “x” on the screen demanded a different reaction. The reactive system comes into play when something happens that is not expected. You have to adapt your behavior and react to the new information, to come up with a new plan.”
Premature babies use their brains differently
The study results showed that the premature participants completed the tasks like everyone else, but they used different cognitive functions to do so.
“What we found was that the premature group had less proactive but more reactive brain activation compared to the normal birth weight control group,” the researcher said.
This signature of hyper-reactive brain activation was accompanied by poor white matter organization in the brain and was associated with impaired intelligence and anxiety.
“Their brain reacted as if they were encountering something new every time,” he explained. “This suggests that their brain is hypervigilant due to suboptimal central nervous system organization. They are less prepared and more surprised each time, which could create more anxiety issues.”
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