Powered by a rechargeable battery, the electronic stimulator delivers millions of impulses to the tongue in a typical 20- minute session. The wafer-thin stimulator (one millimeter thick) is about two inches long and slightly less wide than the tongue.

As Danilov explains it, two major nerves in the tongue are connected to the brain stem, a region in the back of the brain that controls a variety of housekeeping functions, such as heart rate, breathing and consciousness. These are things we seldom pay attention to but that we couldn’t get along without. This stimulation, when received by the brain stem, in effect branches out and stimulates many parts of the brain, effectively repairing it.

“We’re not treating MS; we’re recovering the damaged functions of MS,” Danilov says. “We’re seeing the ability of the brain to change. The brain is fixing itself.”

The idea of the brain’s plasticity — being able to repair itself in this way — was pioneered in the 1960s by the late Paul Bach-y-Rita, M.D., a neuroscientist who worked at the University of Wisconsin.

At the time, it was a heretical notion, explains Kurt Kaczmarek, Ph.D., an engineer and a scientist who worked with Bach-y-Rita and who now works with Danilov, because back then, the prevailing view was that the brain became fixed during adulthood and thus lacked the ability to change. But through hard work and thought (like Bach-y-Rita’s), that view has been proved wrong. Famously, in the late 1950s, when his father suffered a stroke, Bach-y-Rita and his brother had their father do physical activities like sweeping the porch instead of simply resting in a nursing home. This led to their father recovering physical abilities that had been damaged by the stroke.

“The thought is that at each incremental step, the brain is improving itself. That’s what we believe the tongue stimulation is doing — enhancing what the brain is already capable of,” Kaczmarek says.

A major goal of Kaczmarek and his colleagues is to find out how far these “ interventions” — a term he favors over the word treatment — can push the brain to repair itself.

Exactly how that repair happens isn’t certain, admits Danilov. But there are several possible mechanisms. Pointing to a drawing of the brain stem on his office wall, he demonstrates how the impulses from the tongue travel to the brain stem and then either a) go directly to other parts of the brain via neural pathways; b) stimulate certain nerves in the reticular formation, a structure in the brain stem, which may in turn “activate the whole brain”; or c) stimulate brain stem neurons, leading to the release and diffusion of multiple neurochemical compounds (including the neurotransmitter serotonin). The brain stem activation then helps coordinate muscular activity, balance and the transmitting of information from the eyes and ears. It may also send signals to muscles involved in breathing, voice, speech and swallowing.