The jagged, multicolored images depicted what was going on in the two researchers' heads — two brains in conversation, carrying out an intricate dance of internal activity. This is no parlor trick. The brain-tracking technology at work is just a small part of the quest to answer abiding questions about the workings of a three-pound chunk of fatty tissue with the consistency of cold porridge.
How does this collection of nearly 100 billion densely packed nerve cells, acting through circuits with maybe 100 trillion connections, let us think, feel, act and perceive our world? How does this complex machine go wrong and make people depressed, or delusional, or demented? What can be done about that?
While the brain at rest is not completely understood, "everyone is jumping into this now," Bandettini said. It holds promise for mapping out which parts of the brain work with which others to perform key tasks, he said.
The emphasis in brain mapping these days is not so much about finding particular places that do particular tasks, but rather delineating the circuitry that lets the brain operate.
"No region works in isolation. It's all being communicated across networks," Mather said.
Communication flows along an estimated 150,000 miles of nerve fibers in the average brain. Individual fibers are too fine to see in brain-scanning machines, but they form bundles that can be detected as they cross the deep central portion of the brain.
Those bundles are one focus of researchers who are mapping out the brain's "connectome," the complex web of these connections between areas of gray matter, where thinking takes place.
"Any one patch of gray matter in the brain is literally communicating with hundreds of other distant locations, in ways that actually are very different from how modern computer circuits are wired," says David Van Essen of Washington University.
While computers use their lightning speed to crunch numbers, the brain's "squishy hardware," works with far slower internal communication, he said.
"We're able to do analyses and make inferences in ways that still way outperform computers, because the wiring is different and in some ways just incredibly clever. But we don't understand the rules, the strategies in sufficient detail."
The connectome effort is still in its early phases, he said. But it has already gained one unusual distinction: A colorful scientific depiction of brain connections made the cover of an album by the band Muse.
