The brain does not mature overnight

The brains of children as young as 7 to 11 display similar neural networks as young adults when at rest. However, when completing a task, a child’s neural networks do not engage in the same way as those of adults.

Cognitive functions, such as attentiveness and working memory, develop during childhood and adolescence. Brain imaging has identified the cerebral cortex in the prefrontal and parietal lobes as key to cognitive function. Children’s weaker cognitive skills may be attributable to the fact that the frontal lobes and their associated neural networks take a long time to develop and mature.

In her dissertation, Ping Jiang, MSc, studied the “top-down” regulation of the cortical areas that process visual information among children and young adults as well as the functional engagement of the neural networks consisting of these areas of the brain both at rest and while completing a task. The study involved healthy children between the ages of 7 and 11 and young adults, and employed functional magnetic resonance imaging of the brain as well as 1-back performance tasks, which measure working memory. During the memory tasks, the research subjects observed and recalled images of faces or landscapes while being asked to ignore distracting landscapes and faces that were also being shown.

Jiang found that among children, the regulation of the visual cortex that processes faces was weaker or otherwise less mature during the task than it was among adults. In children, the functional engagement between the prefrontal lobes and the visual cortex that processes faces was weaker than it was in adults, which partially explains why children displayed weaker regulation of the visual cortex. In addition, the activation of the prefrontal lobes during the working memory tasks was weaker in children than it was in adults. Combined, these findings partially explain children’s weaker performance in the working memory tasks.

The dissertation also indicates that when the brains are observed at rest, children between the ages of 7 and 11 display similar neural networks to young adults. However, the functional engagement of these networks, particularly while completing a task, was different in children and adults.

 “The differences in the brain activation and functional engagement of neural networks that we observed in  children and young adults can partially be attributed to the stage of morphological development of the grey and white matter in the brains of children aged between 7 and 11. At that stage, synapses are being discarded, and the myelin sheaths that protect nerve fibres are being generated,” says the doctoral candidate.

The dissertation supports the understanding that as children grow, the functional engagement of the prefrontal lobes and the brain’s neural networks changes gradually, meaning that a particular cognitive function can be located in different areas of the brain during different stages of life.

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