FINDING THE CORE OF THE BRAIN

摘要

The iconic image of the brain is a misshapen, yellowish lump. Existing technology can show which parts of the lump light up when people think, but a real understanding of how the brain works demands a better picture of the nerve fibers that ferry electrical signals between brain cells. Those fibers, however, are so small and tangled that researchers haven't been able to see them clearly. Now, an international team of scientists has combined a new variation on magnetic resonance imaging with mathematical analysis to generate the first detailed map of the network of connections in the human cortex, the part of the brain responsible for higher-order thinking. Diffusion spectrum imaging-which tracks water molecules moving along nerve fibers-gave the scientists a wiring map of the cortex, revealing points where multiple nerve fibers converged. The scientists then used a mathematical technique to repeatedly prune away the connection points with the fewest links. "If you do it gradually, you end up with a set of nodes remaining that are highly interconnected," says Olaf Sporns, the Indiana University researcher who performed the analysis.