Depressed? Try magnetic treatment

CONTRA COSTA TIMES

WALNUT CREEK, Calif. — A potential new treatm ent for depression involving magnetic pulses applied to the brain is getting a closer look from neuroscientists at the University of California, Berkeley.

Known as Transcranial Magnetic Stimulation or TMS, the magnetic therapy has shown promise in clinical trials, but scientists have little understanding of how it alters brain function.

Now, Ralph Freeman and a team of graduate students led by Elena Allen at UC Berkeley have taken a big step toward demystifying TMS. They discovered that how the brain stimulation affects neurons depends on what the brain is doing at the time.

Their findings could help psychiatrists better understand how to apply TMS.

“We have to know how it works before we can know how to use it,” said psychiatrist Sarah Lisanby, director of the brain stimulation division at Columbia University in New York.

In a TMS treatment, a paddle containing a coil with electric currents pulsing through it is placed on a patient’s scalp. The currents create a magnetic field in the underlying area of the brain, which changes the electrical signals sent by neurons.

To figure out what exactly TMS does to neurons, Freeman’s team tested it on the brains of anesthetized cats, in the area that processes what the eyes see.

Using a surgically implanted probe to measure the activity of neurons, they found that after a few seconds of TMS, the neurons fired more rapidly for a minute, and then slowed down for several minutes.

But when the same pulses were applied while the cats were exposed to black and white bars flashing across a computer, which can be registered by the brain even under anesthesia, the TMS had a different effect. Instead of boosting brain activity, it slowed neuron firing for several minutes.

Though Freeman may be just scratching the surface of the magnetic effect, his study, which appeared in the Sept. 28 issue of Science, is an important step toward understanding TMS.

“It tells us a little bit about what the effects are,” he said. “So you have a better idea what to try and what not to try.” Though it has not yet been approved by the FDA for use on people, the agency is currently reviewing a TMS treatment device. The method has been approved in Canada, and is used in other parts of the world including Europe, Australia and South America.

Psychiatrist Bret Schneider, a consulting assistant professor at Stanford University, has had success in his private practice using TMS to treat patients with depression that haven’t been helped by drugs.