The Brain at Work
Excerpt By Ned Potter, ABCNews.com

A new imaging device can measure the electrochemical signals produced by thoughts and reaction inside the brain.

Scientists call it M.E.G. — short for Magnetoencephalography — a scanner capable, unlike any before it, of showing activity in the brain as it happens.

"If the brain is trying to do something with information from the outside world, and all the different parts are working a little bit out of synchronization, then the whole picture won't emerge in a coherent kind of way," said Claudia Tesche, a psychologist who helped design the scanner. "We need to know how the brain is processing information on a moment-to-moment basis."

"We can look at changes in brain activity on a millisecond level," said Cheryl Aine of the University of New Mexico, one of the leading researchers in the field.

Electrochemical Signals

The M.E.G. scanner makes that possible because the brain actually runs on tiny pulses of electricity. Every thought, every reaction you have to something, becomes a series of minute electrochemical signals among the cells in your brain.

Weak as those signals are, they can be measured by the 122 sensors in the M.E.G. scanner that surround one's head. The scanner is extremely sensitive, and must be shielded so that it is not overloaded by all the other electromagnetic noise around us. Its ability to detect brain signals amid everything else, says one researcher, is comparable to "being able to hear an insect's footsteps — at a rock concert."

"We can get a picture — a very clear picture — of what's going on inside someone's head without touching them at all," said Michael Weisend, a researcher who has worked extensively with M.E.G. "You just get to sit down and look at the operation of the living brain."

In the imaging center at the New Mexico Federal Medical Center in Albuquerque, we were introduced to a woman named Annie. Three years ago, she began to show symptoms of schizophrenia — unable to distinguish reality from illusion.

"I started getting paranoid that they were going to come and kill me while I was sleeping, and so I started sleeping in my car," she said.

With medication, she's now much better, but doctors would like to know what goes on inside her head. So Aine ran her through a test of cognitive abilities, while she sat with her head in the scanner.

Order and Chaos

When the results are processed by computer, they generally show the workings of the human brain to be remarkably orderly. If an image is flashed on a screen in front of a healthy person, for example, the scanner shows a response in a region in the back of the brain that processes vision.

If the image happens to be of a word, the activity will transfer to the frontal lobe, which handles higher logic and language. The M.E.G. scan shows that all this happens in about half a second.

"The schizophrenic doesn't do that," said Tesche. "The activity keeps fluttering around from one brain area to another."

The result is chaos — a harmless picture may inadvertently be processed by parts of the brain that usually process touch, or taste, or even fear. It may, scientists surmise, explain why people with schizophrenia sometimes hallucinate.

But researchers now have unprecedented ability to see what is going wrong in the brain — in schizophrenia, epilepsy, and many other disorders — and, perhaps, armed with the new information, find cures.

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