A time-lapse 3-D movie that compresses 15 years of human brain maturation, ages 5 to 20, into seconds shows gray matter the working tissue of the brain's cortex diminishing in a back-to-front wave, likely reflecting the pruning of unused neuronal connections during the teen years. Cortex areas can be seen maturing at ages in which relevant cognitive and functional developmental milestones occur. The sequence of maturation also roughly parallels the evolution of the mammalian brain, suggest Drs. Nitin Gogtay, Judith Rapoport, NIMH, and Paul Thompson, Arthur Toga, UCLA, and colleagues, whose study is published online during the week of May 17, 2004 in The Proceedings of the National Academy of Sciences.
"To interpret brain changes we were seeing in neurodevelopmental disorders like schizophrenia, we needed a better picture of how the brain normally develops," explained Rapoport.
The researchers scanned the same 13 healthy children and teens every two years as they grew up, for 10 years. After co-registering the scans with each other, using an intricate set brain anatomical landmarks, they visualized the ebb and flow of gray matter neurons and their branch-like extensions in maps that, together, form the movie showing brain maturation from ages 5 to 20.
It was long believed that a spurt of overproduction of gray matter during the first 18 months of life was followed by a steady decline as unused circuitry is discarded. Then, in the late l990s, NIMH's Dr. Jay Giedd, a co-author of the cu
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