An international research group has shed light on the changes in the neural network and the cortex structure of the brain that underlie the positive relationship between children’s movement and the maintenance and promotion of cognitive functions later in life. The results, published in the journal NeuroImage, explain that people who are physically active in childhood have higher cognitive functions later in life.
Participants who trained as children did better on cognitive tests regardless of their current age. However, no such association has been found between task performance and post-childhood exercise – suggesting that childhood exercise is particularly important for brain development and long-term cognitive health.
The researchers showed that people who are physically active in childhood (up to the age of 12) have higher cognitive functions later in life. However, they could not find a link between cognitive function and physical activity after childhood. The positive relationship between children’s movement and cognitive function was shown in the modular (* 1) separation of brain networks, increased interhemispheric connectivity, greater cortical thickness, less dendritic branching and reduced density. During childhood, the formation of the brain’s network is susceptible to environmental and experiential factors. It is believed that exercise during this time optimizes the development of the brain network and is linked to the maintenance and enhancement of cognitive function later in life. Research over the past decade has shown that childhood exercise affects the development of cognitive functions.
Recent evidence has shown that these benefits of exercise in childhood extend to the maintenance and enhancement of cognitive function in middle and later life. However, the changes in brain function and structure associated with this positive association have yet to be illuminated. This research study examined the relationship between physical activity in childhood and cognitive function later in life, using MRI (magnetic resonance imaging) to shed light on the structural and functional changes in the brain that are behind this relationship.
The research group conducted a study of 214 participants, ages 26 to 69, to investigate the relationship between childhood movement and cognitive function, as well as the underlying functional and structural neural networks and cortical structure. Movement in childhood was recorded using a questionnaire. One aspect of cognitive function, reaction inhibition (the ability to suppress inappropriate behavior), was measured using a go / no-go task. The image data from the MRI were analyzed and calculated: structural and functional connectivity (* 2), cortical thickness, myelination, degree of neurite orientation scatter and density index.
The brain was divided into 360 areas according to the Human Connectome Project (* 3) and functional and structural parameters were determined for each area. Information from the questionnaire was used as disruptive factors in the statistical analysis. This included the educational background of each participant, the educational background of the parents, the number of siblings, and exercise in adulthood.
First, the researchers analyzed the relationship between whether participants exercised during their childhood and go / no-go task performance (false alarm rate). They found that participants who exercised during childhood (up to the age of 12) had a lower rate of false positives than those who did not (Figure 1). In addition, this relationship was found regardless of the age of the participants. However, no such association was found between task performance and post-childhood movement.
Next, the research group examined the structural and functional connectivity in the brain in relation to performing go / no-go tasks in participants who exercised during childhood. From these results, they confirmed that in terms of structural connectivity in the rain, there were positive associations (Figure 2A: connections in red) and negative associations (Figure 2A: connections in blue) between movement during childhood and the false alarm rate in the Go / No-go task. Large-scale network connectivity was found in over half (73 percent) of the structurally connected areas, which was positively associated with the false alarm rate of the go / no-go task (Figure 2B, left panel).
On the other hand, interhemispheric connectivity was found in the majority (88 percent) of the structurally connected areas that were negatively related to the false alarm rate of the task (Figure 2B, right panel). Regarding connections between functional areas, connections with positive associations (Figure 3A: Connections in red) with the false alarm rate of the go / no-go task were identified in participants who trained in childhood, but no negatively associated connections were found.
In addition, large-scale network connectivity was found in the majority (91 percent) of the connected areas, which was positively associated with the false alarm rate of the task (Figure 3B, left panel). No structural or functional connectivity related to the false alarm rate in the go / no-go task was identified in the participants who did not exercise during childhood. Finally, the researchers examined cortical structural parameters related to the go / no-go false alarm rate for participants who exercised as children.
They found that task performance was negatively associated with cortical density and positively associated with the degree of neurite orientation scatter and density. The above results show that modular segregation and increased interhemispheric connections in the brain networks of people who exercised during childhood reduced the number of mistakes they made in the go / no-go task.