Small world in your head

Inspired by the same mathematics behind "six degrees of Kevin Bacon," neuroscientists are creating models of how the human brain work. In this "small world" architecture of the brain, clusters of cells link to their nearest neighbors with some neurons connecting to distant clusters. It's the same phenomenon that social networking pioneer Duncan Watts of NYU and Steven Strogatz of Cornell previously showed emerges in the electric-power grid, relationships between professional actors, and the brain cells of worms. According to Strogatz and Watts, this kind of small world structure boosts the power and efficiency of the system. Often, the networks behave chaotically. From Science News:

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…Scientists are looking for small-world setups within the brain's massive, interconnected cell networks and for moment-to-moment electrical manipulations that, they suspect, foster thinking and learning. Their efforts are a sharp departure from popular brain-imaging efforts to pinpoint neural niches that specialize in particular mental capabilities.

"Researchers have just begun to apply a huge arsenal of approaches to understanding how brain networks are patterned, how they evolve and grow, and how they generate dynamic structures," says neuroscientist Olaf Sporns of Indiana University in Bloomington…

The notion that the brain thrives on chaos, in a mathematical sense, comes as no shock to neuroscientist Walter J. Freeman of the University of California, Berkeley. For the past 20 years, he has argued that the brain churns out a cascade of chaotic electrical activity that serves as a "get ready" state. From there, he theorizes, vast expanses of brain tissue shift into electrical-activity patterns that organize thought and perception.

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