Introducing a New Method to Stimulate the Brain

Magnets could be used to induce long-lasting brain tissue stimulation.

Kristopher Sturgis

A novel method of stimulating brain tissue using external magnetic fields allows for the direct stimulation of neurons. Made possible by the manipulations of magnetic nanoparticles, the method could serve as an effective treatment for a variety of neurological diseases.

The research, overseen by scientists at MIT, is part of a larger effort at the university to explore alternative methods of delivering stimuli to the nervous system in a wireless, and ultimately less invasive manner, according to a news release out of MIT.

In the study, researchers injected magnetic iron oxide particles 22 nanometers in diameter into the brain. When exposed to an external alternating magnetic field, these iron oxide particles rapidly heat, resulting in localized neural activation. The advantages of using the external magnetic field is that it is noninvasive and can penetrate deep inside biological tissue, enabling the particles to trigger heat-sensitive capsaicin receptors, serving as a catalyst for tissue stimulation.

The particles also have virtually no interaction with biological tissue apart from when they are heated, meaning they tend to remain in place at the site of injection, allowing for long-term treatment without any need for future invasive procedures. The team believes the work thus far could pave the way for practical applications in brain research and clinical treatments.

Neuroscientists from around the world continue to explore alternative brain stimulation methods that are less invasive than yet as effective as traditional techniques. One example is a wearable device that stimulates the brain through the tongue, designed to help treat traumatic brain injuries through targeted neural stimulation.

Meanwhile, last summer, the Defense Advanced Research Projects Agency (DARPA) awarded contracts to Massachusetts General Hospital and the University of California, San Francisco to create electrical brain implants aimed at treating various psychiatric conditions.

Admittedly, the concept behind the MIT research derives from an active area of cancer research that's been explored over the last several years, using magnetic fields and injected particles as an approach to destroy cancer cells by heating them up. Researchers theorized that by calibrating the delivered thermal dosage, they could excite neurons without killing them, acting instead to stimulate the tissue.

While this study remains more of a proof-of-concept for now, the team believes their approach is particularly imaginative as it can be remotely controlled and provides an alternative to invasive surgical techniques. Administering magnetic doses is straightforward and could act as a long-term treatment option for neurological diseases and brain injuries that can be treated through brain tissue stimulation.

The researchers plan on using neural recordings and behavioral experiments to better understand how it works. They also plan to assess whether or not there will be side effects to tissue in the affected area, and hope to ultimately ready the technique for clinical use.

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