Scientists at the National Institute of Mental Health (NIMH) in collaboration with the University of California, Los Angeles, developed a new brain mapping technique and applied it to high quality MRI scans of children scanned across ages 4 through 21. This allowed them to visualize the dynamics of brain development including the cortex. They also constructed the first three-dimensional movie of human brain development.
The cortex, or surface of the brain, is also called the "gray matter" where the neurons, or the main brain cells, reside along with their immediate connections or synapses. After birth, an initial overproduction of synapses- which are within the gray matter - is followed by their systematic pruning with maturation. For most of the cortex, this maturation begins right before puberty.
"While confirming that the cortical gray matter maturation is a temporally uneven process, we found that the normal gray matter loss begins first in the motor and sensory parts of the brain (the top-middle portion), slowly spreading downwards and forwards, over the entire brain surface," says Nitin Gogtay, MD. "The surprising thing is that the sequence in which the cortex matures appears to agree with regionally relevant milestones in cognitive development, and also reflects the evolutionary sequence in which brain regions were formed," he says.
Parts of the brain associated with more basic functions matured early: primary motor and sensory brain areas matured first followed by areas involved in spatial orientation, speech and language development, and attention (upper and lower parietal lobes), spreading to the areas involved in executive functioning, attention or motor coordination (frontal lobes). F
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Contact: Dawn McCoy
dawn@sfn.org
202-462-6688
Society for Neuroscience
8-Nov-2003