Why There Are No Crashes on Your Brain's Information Superhighway

This is sort of what your brain networks look like, but instead of signals traveling on different ramps, they travel on different frequencies.
This is sort of what your brain networks look like, but instead of signals traveling on different ramps, they travel on different frequencies.

F. Scott Fitzgerald once wrote, "The test of a first-rate intelligence is the ability to hold two opposed ideas in mind at the same time and still retain the ability to function."

In a less metaphysical sense, the sign of a well-working brain is the ability of multiple networks to work at the same time, even if they have opposing goals -- say, the network that controls the various muscle systems that get you to run and the network that controls the part that thinks over and over, "I hate this."

How can one part of the brain participate in multiple networks simultaneously? A team of researchers, comprised of scientists from Washington University Medical School and the University Medical Center at Hamburg-Eppendorf and the University of Tübingen, both in Germany, have had a brain wave.

Or, rather, it has to do with brain waves.

Using a newfangled technique called magnetoencephalography (MEG), the scientists analyzed the brain activity of 43 volunteers at the University Medical Center at Hamburg-Eppendorf. MEG is more sensitive than magnetic resonance imaging (MRI), the technique most brain researchers had been using before. Instead of measuring blood flow -- the areas with the most blood flow are the most active -- MEG tracks small changes in magnetic fields in the brain. The fields change when the more cells are active.

"Magnetic resonance imaging is a useful tool, but it does have limitations," explained Dr. Maurizio Corbetta, one of the Wash. U. scientists. "It only allows us to track brain cell activity indirectly, and it is unable to track activity that occurs at frequencies greater than 0.1 hertz, or once every 10 seconds. We know that some signals in the brain can cycle as high as 500 hertz, or 500 times per second."

And indeed, the more sensitive mechanism of MEG revealed that different brain systems operate at different frequencies. The area of the brain responsible for memory is active at 5 hertz, but areas that controlled the senses and movement operated between 32 and 45 hertz.

"We found that different brain networks ticked at different frequencies, like clocks ticking at different speeds," said Joerg Hipp, one of the German researchers.

So what practical good is this, besides allowing scientists to play with a cool new toy?

Well, in the words of Corbetta: "Many neurological and psychiatric conditions are likely to involve problems with signaling in brain networks." These include a wide range of diseases and disorders, from depression to schizophrenia. Most of these diseases don't have physical symptoms, so they go undetected until they cause changes in behavior. By then, they're usually in full swing.

Corbetta hopes that the new MEG technology will help detect these disorders when it's still possible to prevent them. As he says, in doctor-speak: "In the future, this might offer new diagnostic tests or ways to monitor the efficacy of interventions in these debilitating mental conditions."

A report of the study, which was funded by the European Union, appears in this month's issue of Nature Neuroscience.

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