Science: Researchers Report the Hallmarks of a Mature Brain

Functional brain connections important for predicting the functional maturity of individual brains from magnetic resonance imaging (MRI) scans. The thickness of each connection indicates its relative weight in predicting brain maturity. Functional connections that grow stronger with maturation are shown in orange, whereas those that weaken with maturation are shown in green.

Image © Science/AAAS

How does the human brain change as a child grows through his or her tumultuous teen years into adulthood? According to a new study, a thorough analysis of a five-minute brain scan is all researchers need to provide some measure of the brain's maturity level.

Nico Dosenbach from Washington University in St. Louis School of Medicine, along with colleagues from across the United States, analyzed 238 functional connectivity magnetic resonance imaging (fcMRI) brain scans from volunteers—7 to 30 years old—with sophisticated pattern analysis software to explore how the human brain matures over time. Their study is published in the 10 September issue of the journal Science.

“We wanted to take our analyses to the single subject level and make meaningful decisions about individuals,” said Dosenbach of the study. “Based on our previous group level analyses, we were confident that we could apply machine learning diagnostics and prognostics to the study of typical development.”

Specifically, their results show that the strength of long-range neuronal connections in the brain tends to increase with age while short-range connections tend to get weaker over time. The researchers note that the loss of short-range connections in the brain seems to be more indicative of brain maturity than any other factor. They also propose that a mature brain would be characterized by sparser, yet sharper, neuronal connections throughout.

Dosenbach and his colleagues even suggest that a quick, five-minute fcMRI scan of the brain could become standard practice in the future to aid doctors in screening, diagnosing, and treating patients with disordered brain function.

“The functional connectivity maturation index would be most helpful as an all purpose screening tool for developmental aberrations of various origins,” said Dosenbach. “Clinicians could even track it longitudinally to monitor their patients with known disorders, for example, to assess their responses to various therapies. Hopefully, in the future, we'll be able to develop diagnostic machines tailored to diagnose specific disorders, such as autism.”

Brandon Bryn

9 September 2010