Kristen V. Brown | Gizmodo | Source URL
How did a Massachusetts woman end up with two electrodes implanted into her brain? Why is the Defense Advanced Research Projects Agency developing a controversial, cutting-edge brain chip technology that could one day treat everything from major depressive disorder to hand cramps? How did we get to deep brain stimulation and where do we go from here?
In 1848, a rail foreman named Phineas Gage was clearing a railroad bend in Vermont when a blast hole exploded, sending the tamping iron he had been using to pack explosives through his left cheek, his brain’s left frontal lobe and finally out the top of his skull before landing 25 yards away, stuck upright in the dirt. Despite his pulverized brain mass, Gage went on to make a full recovery, with the exception of a blinded left eye. It was, by all accounts, miraculous.
But while Gage could walk and talk, those who knew him found that after the accident he seemed, well, different. A local physician who treated him the day of the accident observed that “the equilibrium … between his intellectual faculties and his animal propensities seems to have been destroyed.” His friends put it more simply: Gage, they said, “was no longer Gage.”
Gage’s case was the first to suggest the link between the brain and personality—that the brain is intimately connected to our identity, our sense of self.
Since then, science has frequently exploited that link in the name of (sometimes misguided) self-improvement. Change the brain, and change the self. Once-common but in hindsight abhorred lobotomies were the first treatment to offer relief from mental illness by disrupting the brain’s circuitry, severing the connections to and from the prefrontal cortex. Electroconvulsive therapy, a once-cutting edge treatment now reserved for extreme cases, sends a shock of electric current through the brain for a near-instant change in its chemical balance. Antidepressants target neurotransmitters like serotonin to affect mood and emotions.
As we have unpacked more thoroughly the mysteries of the brain, we have become better able to precisely target the changes we want to affect.
This is how Liss Murphy wound up with two 42-centimeter-long electrodes implanted deep within the white matter of her brain.
For years, Murphy had suffered from severe depression that seemed untreatable—rounds of Effexor, Risperdal, Klonopin, Lithium, Cymbalta, Abilify, electroshock therapy and even an adorable new puppy failed to get her up out of bed. Then doctors offered her a new option, something called deep brain stimulation.
On June 6, 2006—6/6/06—doctors at Massachusetts General Hospital drilled two holes into Murphy’s skull and implanted two electrodes into a dense bundle of fibers within her brain’s internal capsule. The axons here carry signals to many of the brain’s circuits that have been linked to depression. Those electrodes were then connected to two wires that ran behind her ears and under her skin to her clavicle, where two battery packs just slightly larger than a matchbox were implanted to power them. When turned on, the hope was that the electrical signals emitted by Murphy’s new implants would in effect re-wire the circuits in her brain that were causing her to feel depressed.
It worked. Murphy became one of the first people in world successfully treated for a psychiatric illness using deep brain stimulation, in which electronic neurostimulators are embedded deep within the brain to correct misfiring signals. Like Gage, the experience changed her, but for the better. She got out of bed, had a kid, and went back to work part-time after years of being able to barely leave the house.
“My greatest hope the day of the surgery was that I would die on the table,” Murphy recently told Gizmodo. “I can cobble together a regular day now. It truly gave me my life back.”
Deep brain stimulation is the bleeding edge of mental health treatment. Originally developed to treat the terrible tremors that patients with Parkinson’s disease suffer from, many researchers now view it as a potentially revolutionary method of treating mental illness. For many patients with mental health disorders like depression, therapies like drugs are often insufficient or come with terrible side effects. The numbers are all over the place, but doctors and researchers generally agree that significant numbers of people don’t respond adequately to current treatment methods—one often-cited study pegs that number somewhere around 10%-30%. But what if doctors could simply open up the brain and go directly to the source of a problem, just as a mechanic might pop open the hood of a car and tighten a loose gasket?
Now, the same team that implanted electrodes into Murphy’s brain is halfway through a five-year, $65 million research effort funded by the Defense Advanced Research Projects Agency to use the same technology to tackle some of the trickiest psychiatric disorders on the books. The goal is ambitious. DARPA is betting that the research teams it is funding at Mass. General and UCSF will uncover working therapies for not just one disorder, but many at once. And in developing treatments for schizophrenia, PTSD, traumatic brain injury, borderline personality disorder, anxiety, addiction and depression, along the way their work also aims to completely reframe how we approach mental illness to shed new light on how it flows through the brain.
“This is a radical departure from traditional neuropsychiatric illness treatment,” said Justin Sanchez, the director of DARPA’s Biological Technologies Office. “We’re talking about being able to go directly to the brain to treat people. That’s transformative.”
Unfortunately, it’s not quite as simple as all that.
For starters, psychiatric illnesses are complicated, and often not all that well understood in terms of where they exist in the brain. For more than a decade, DBS has been used in patients with Parkinson’s disease, but targeting the brain’s motor cortex to manage Parkinson’s violent trembling is a lot less complicated than targeting, say, depression. A diagnosis of major depressive disorder requires that a person exhibit five of nine symptoms, but two people could be depressed and have almost no symptoms in common. That means that for those two people, treating depression with deep brain simulation might require stimulating entirely different regions of their brain. And there is still disagreement about what those regions even are.
Then there is the array of ethical questions that brain technologies like DBS inspire. Does inserting a chip into someone’s brain to mediate their brain circuitry change their identity? Might it, eventually, lead to the ability to simply treat ourselves when feeling blue, a sort of high-tech take on Aldous Huxley’s soma? Could you use a DBS device to hack into someone’s brain? Or control them? Or enhance them? Is it potentially dangerous in the wrong hands?
Rumors have swirled that the DARPA’s real goal in all this research is to create enhanced super soldiers. The agency has several other brain computer interface projects, which seek not just to use chips to treat mental illness, but also to restore memories and movement to battle-wounded soldiers. A 2015 book about about the history of DARPA, “The Pentagon’s Brain,” suggested that government scientists hope that implanting chips in soldiers will eventually unlock the secrets of artificial intelligence and allow us to give machines the kind of higher-level reasoning that humans can do, or allow soldiers to perform feats like waging war using their thoughts alone. DARPA, though, has maintained that its main goal is to develop therapies for the many thousands of soldiers and veterans with wounded brains.
Murphy was among the first mental health patients to be successfully treated using DBS, but the idea that we might use electrical signals to right our sometimes faulty wiring is by no means a new one. In the 1970s, a Yale University neuroscientist named Jose Delgado implanted radio-equipped electrode arrays—he called them “stimoceivers”—into cats, monkeys, bulls and even humans. His work demonstrated that electrically stimulating the brain could elicit movement and on occasion even particular emotions.
In one now famous experiment, Delgado agitated the temporal lobe of a young epileptic woman while she calmly played the guitar, prompting her to react by violently smashing the guitar against the wall in rage. Less sensational, but more promising for clinical purposes was Delgado’s research that found stimulating a part of the human brain’s limbic region called the septum could invoke euphoria strong enough to counteract depression, and even pain.
In 1970, The New York Times Magazine hailed Jose Delgado as the “impassioned prophet of a new ‘psychocivilized society’ whose members would influence and alter their own mental functions.” They also called it “frightening.” His work eventually became engulfed in controversy. Strangers accused him of having secretly implanted stimoceivers into their brains. Delgado, who was Spanish, left the U.S. shortly after Congressional hearings in which he was accused of developing “totalitarian” mind-control devices. His work receded into the archives of history.
More recent forays into deep brain stimulation began in 1987, when a French neurosurgeon named Alim Louis Benabid was preparing to remove a piece of the thalamus in a patient who suffered from severe tremors, a then-common practice known as lesioning that aimed to calm problematic areas of the brain by surgically damaging them. While probing the thalamus to ensure he didn’t accidentally remove something crucial, he inadvertently discovered that jolts of electricity could stop the tremors, no brain damage necessary. A little more than a decade later, the U.S. Food and Drug Administration approved DBS for use in patients with Parkinson’s disease. Today, there are over 100,000 Parkinson’s patients with tiny chips in their brain to control their symptoms. Parkinson’s is still the most common use of DBS. In 2009, the FDA approved a humanitarian exemption to allow patients with severe obsessive-compulsive disorder to receive implants. All other uses of DBS are considered experimental.
Case studies of patients who have received the treatment have shown that those implants sometimes have severe side effects.
In one case study, a 43-year-old man suffering from debilitating Tourette’s Syndrome received DBS. His doctors targeted well-known areas of the brain considered safe for treatment in order to relieve his tics. And it worked. But a year after the operation, he began to dissociate from his previous self. Doctors observed that increasing the amount of electrical stimulation in his brain resulted in him “anxiously crouching in a corner, covering his face with his hands” and speaking “with a childish high-pitched voice.” When it was decreased, he went back to normal, with little memory of what had happened. A 2015 review of cases using DBS to treat Tourette’s found that Tourette’s patients seem more likely to experience post-DBS complications, but ultimately concluded the treatment still seemed promising, citing successes.
Another study found that 20% of 29 Parkinson’s patients reported experiencing an altered body image due to a DBS brain implant, telling researchers things like I “feel like a machine.”