Last year I reported on a study involving 210 subjects aged 7 to 31 that found that in contrast to the adult brain, most of the tightest connections in a child's brain are between brain regions that are physically close to each other. As the child grows to adulthood, the brain switches from an organization based on local networks based on physical proximity to long-distance networks based on functionality. Now the same researchers, using five-minute scans from 238 people aged 7 to 30, have looked at nearly 13,000 functional (rather than structural) connections and identified 200 key ones. On the basis of these 200 connections, the brains could be identified as belonging to a child (7-11) or an adult (25-30) with 92% accuracy, and adolescents or adults with 75% accuracy. Moreover, the most important factor in predicting development (accounting for about 68%) was the trimming of the vast number of childhood connections.
Apart from emphasizing the importance of pruning connections in brain development, the main value of this research is in establishing an effective analytic method and baseline measurements for normal development. It is hoped that this will eventually help researchers work out indicators for various developmental disorders.
(2009). Functional Brain Networks Develop from a “Local to Distributed” Organization.
PLoS Comput Biol. 5(5), e1000381 - e1000381.
(2010). Prediction of Individual Brain Maturity Using fMRI.
Science. 329(5997), 1358 - 1361.