In mice, the researchers found that sensory deprivation prevented the substantial loss of synapses that typically occurs in growing animals. The effects were most pronounced in the period from young adolescence to adulthood. Synapses are the gaps between neurons through which information travels.
Wen-Biao Gan, Ph.D., Assistant Professor of Physiology and Neuroscience, and his colleagues captured images of brain plasticity--its ability to adapt quickly to ever-changing circumstances--and have started to unravel how this dynamic unfolds. The scientists were able to deliver visible evidence of the effect of sensory deprivation.
It is well known that a growing child learns many skills. "What is less known," says Dr. Gan, "is that during childhood until puberty in the human brain, as well as in the monkey and mouse, you see a substantial loss of neuronal connections." In learning, it appears the brain needs to lose as it gains. He believes this loss may well be the fundamental process underlying the development and plasticity of the brain.
After birth, the number of synapses increases and then decreases sharply. From early childhood to adolescence the synaptic loss could be as much as 50 percent.
Dr. Gan believes that in order for learning to occur, the brain's neurons have to be pruned. "First there is a raw material, and then it is sculpted," he says. In other words, learning isn't only about making new connections between neurons, he says, it also involves carving neuronal connections.
The authors of the new study are Yi Zuo, Guang Yang, Elaine Kwon, and Dr. Gan of the Molecular Neurobiology Program at the Skirball Institute of Biomolecular Medicine at NYU Schoo
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Contact: Marjorie Shaffer
Marjorie.Shaffer@nyumc.org
212-404-3555
New York University Medical Center and School of Medicine
13-Jul-2005