Imagine if your biggest health problem could be solved with the flip of a switch. Deep-brain stimulation (DBS) offers such a dramatic recovery for a range of neurological illnesses, including Parkinson's disease, epilepsy and major depression. Yet the metal electrodes implanted in the brain are too bulky to tap into intricate neural circuitry with precision and corrode in contact with tissue, so their performance degrades over time. Now neurophysiologists have developed a method of DBS that avoids these problems by using microscopic magnets to stimulate neurons.

In experiments published in June 2012 in Nature Communications, neurophysiologist John T. Gale of the Cleveland Clinic and his colleague Giorgio Bonmassar, a physicist at Harvard Medical School and an expert on brain imaging, tested whether micromagnets (which are half a millimeter in diameter) could induce neurons from rabbit retinas to fire. They found that when they electrically energized a micromagnet positioned next to a neuron, it fired.

In contrast to the electric currents induced by DBS, which excite neurons in all directions, magnetic fields follow organized pathways from pole to pole, like the magnetic field that surrounds the earth. The researchers found that they could direct the stimulus precisely to individual neurons, and even to particular areas of a neuron, by orienting the magnetic coil appropriately. “That may help us avoid the side effects we see in DBS,” Gale says, referring to, for instance, the intense negative emotions that are sometimes accidentally triggered when DBS is used to relieve motor problems in Parkinson's.

The micromagnets also solve other problems associated with metal electrodes. The magnetic field easily penetrates the magnets' plastic coating, which prevents corrosion and the ensuing inflammation of brain tissue. “I've been doing DBS research for 14 years now, and this is a totally different way of thinking about activating the brain for me, which is very exciting,” Gale says.

Although the study focused on stimulating neurons, micromagnets could be used to activate other excitable tissues, such as in the heart, inner ear or muscles in our extremities, as part of a pacemaker or prosthetic device. In humans, the micromagnets would be turned on and off by an external control pack, either wirelessly or by connecting to a wire implanted under the skin. A medical company has acquired the rights to manufacture the micromagnets, and if animal research continues to show them to be safe and effective, these devices could be tested in humans within five years, according to Gale.

This article was originally published with the title Stimulating the Brain with Microscopic Magnets.

10 Comments

1. 1. Traveler 007 09:05 AM 1/31/13

   They installed the magnets in my head and I got stuck to the refrigerator for 2 days. Oh well at least I had food.

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2. 2. cbung 09:25 AM 1/31/13

   A possible eventual brain|computer interface. Those devices used to treat illnesses will someday be re-purposed into other capabilities. It's not hard to imagine small magnets also responding to nerve impulses however minutely, and so creating a detectable feedback signal. The cyborg may be a perfectly healthy but plugged in individual.

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3. 3. littleredtop 01:30 PM 1/31/13

   This is further evidence that there may have been some legitimacy associated with the magnet hat once offered for sale through ads in the classified sections of various magazines and comic books. The magnet hat was filled with tiny magnets that could be repositioned to stimulate specific sections of the brain. The hat was rather heavy and not easily adjusted besides being hot and uncomfortable. The user was required to wear the hat for long periods of time while reading or studying. As a grade school student I had a friend that sent off for one of those hats. He wore it in class one day and our teacher confiscated it and never gave it back to him. I always pictured the old bag wearing the hat while taking her nightly bubble bath etc.

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4. 4. Hypatia2 in reply to littleredtop 01:52 PM 1/31/13

   How do you know the teacher was an "old bag"?
   
   You just told us something revealing about you.

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5. 5. Hypatia2 in reply to EmelenHilliard 03:40 PM 1/31/13

   Can't SA do something to head off these semi-literate plugs for commercial Web sites?

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6. 6. sjfone 01:51 AM 2/1/13

   Damn thorough experiment.

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7. 7. INSeducate 04:36 PM 2/1/13

   Thanks for featuring that work by the team that includes our International Neuromodulation Society member John T. Gale, PhD. More potential breakthroughs are being presented in June at the 11th World Congress in Berlin, http://bit.ly/INScongress.

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8. 8. thiago@sci 08:37 AM 2/2/13

   But, what happens if you put your head into a MRI machine?
   This scares me!

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9. 9. greenhome123 04:35 PM 2/5/13

   i guess if you put your head in an MRI machine the magnets would shoot out of your skull.

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10. 10. bucketofsquid in reply to thiago@sci 05:24 PM 2/7/13

    You wouldn't need an MRI of your head because the magnets could be read directly for an update on your brain. There aren't too many gangs driving around with an MRI in the back of their pickup or van so there is little to fear.
    
    Then again maybe the airport scanners and anti-theft scanners at libraries and stores would make your head explode. Oops!

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