As a child’s brain develops, it becomes more segregated into specialized units, but at the same time, more integrated as a whole due to stronger “hub” connections. These well-defined, networked brain structures are directly related to the healthy development of executive functions, such as the ability to control impulses, stay organized, and make decisions.
In a new study, published in the journal Current Biology, researchers were able to map the changes in the brain that underlie these improvements in executive function. The findings could also lead to the identification of biomarkers of abnormal brain development that could predict a person’s risk for psychosis and major mood disorders.
“We were surprised to find that the developmental refinement of structural brain networks involved increased modular segregation and global integration, since highly modular systems have the potential to become fragmented,” says Ted Satterthwaite, an assistant professor of Psychiatry in the Perelman School of Medicine at the University of Pennsylvania.
“This increasingly modular yet globally integrated network topology may maximize communication efficiency while minimizing wiring costs in the brain.”
The study suggests that modular brain architecture is critical for the development of complex cognition and behavior. In fact, the degree to which executive function improves in a young person is directly associated with how well-defined is his modular network structure.
For the study, the researchers set out to investigate the normal developmental pattern of structural network modules and their relationship to executive functioning. The pulled data from a large sample of 882 youths between the ages of eight and 22 who had undergone diffusion imaging as part of the Philadelphia Neurodevelopmental Cohort, a community-based study of brain development that includes rich neuroimaging and cognitive data.
As expected, executive function improved markedly in study participants with age. An analysis of the brain images revealed an increasingly specialized and fully integrated modular structure.
“The development of modular network architecture did not result in the brain becoming fragmented,” explains the study’s first author Graham Baum, a Ph.D. candidate in the Perelman School of Medicine at the University of Pennsylvania.
“In fact, the overall network communication capacity actually increased, due to strengthening of specific ‘hub’ connections between modules. These results show that as kids grow up, their brain becomes more segregated into specialized units, but also more integrated as a whole.”
The findings suggest that a globally integrated network architecture may be critical for supporting specialized processing and reducing interference between brain systems.
The researchers say they are now combining structural and functional imaging techniques to examine how structural brain networks constrain and shape functional brain networks and activation patterns. They will also be conducting research to determine whether this information can help predict the emergence of psychiatric disorders in children years later.
Source: Cell Press