Smart Implants Intercept Seizures

Image by Henrik Jonsson

A good piece by Aliyah Baruchin in the July SciAm looks at how a new generation of implantable devices may help people with epilepsy squelch seizures before they get out of control. For more than a decade doctors have been implanting Vagus Nerve Stimulators (VNS) into patients who are unresponsive to anti-seizure meds. VNS either sends a periodic stimulating pulse through the vagus nerve or allows patients, when they sense a seizure coming on, to shock themselves with a magnet passed over the implanted device. The electrical stimulation defuses the mounting synchronized brain activity that would, if allowed to mount, culminate in a seizure. VNS works pretty well for a small fraction of patients whose seizures aren't responsive to anti seizure medications.

The avant-garde in implants promises to be much more subtle and targeted. The devices will read signals from the brain and "write" back to it with appropriately limited intervention. By tracking electrical activity (or temperature) in the part of the brain causing the seizures, these devices can tell when seizure activity is imminent and then can have one of three responses to intercept the seizure before it blossoms into disabling spasms or impaired consciousness.

One of these devices, under development at the University of Kansas Medical Center, address a coming seizure by cooling the area of the brain where they are kindling. Others do so by sending an electrical pulse to the offending area as a seizure mounts. A third type delivers anti-seizure medication locally and in limited doses that do not effect the entire brain.

The big advantage of all three delivery systems is that they tailor treatment to actual brain activity rather than constantly treating a brain that may only occasionally be seizure prone.

This will be a big deal for people with epilepsy. But the practice doctors get with implanted read/write devices will change the course of neuroscience and, sooner or later, it will effect everyone. The real-time data that will be collected by these implanted devices will give scientists a huge new window into all kinds of brain activity. And once installing electrodes in brains becomes routine, applications will go well beyond treating brain disorders or enabling prosthetic devices. The Brain Machine Interface is coming; fasten your seat belts.

Thinking Makes it Go

Illustration by Leandro Castelao

Brains and machines have been flirting for decades, but at several centers around the country they are now getting married. Brain surgeon and neuroscientist Edward Chang is the focus of my story about the union, just out in San Francisco magazine. Chang and his colleagues at the UC Berkeley-UCSF Center for Neural Engineering and Prosthetics (CNEP) are developing brain-computer interfaces, including one that will read words from paralyzed patients' brains and give them voice through a prosthetic device.  Jan Rabaey is developing mirco-arrays that will read electrical signals from the cortex's surface and transmit signals through the skull to devices outside. Michel Maharbiz is even talking about "brain dust," networked wireless nanosensors, each the size of a dust mote, that could be distributed throughout the entire brain like artificial neurons and wirelessly communicate with computers in the outside world. “It’s still a vision for the future, but we think it could work,” he says.

Big Picture on BMI

This week's Big Picture Science examines brain-machine interfaces (BMIs). Guests include engineer of the tiny Jan Rabaey, at the Center for Neural Engineering and Prostheses, who is developing wireless micro-electrode grids that can send signals out of human brains;  Human Connectome researcher Arthur Toga,  a UCLA cartographer of human brain function; UCSF neuroscientist Brad Voytek, who studies attention and memory in ECoG-implanted epilepsy patients; and senior UCSC neurobiologist Michael Gazzaniga, author of the recent book Who's In Charge?: Free Will and the Brain. The interviews are excellent, and the show opens up with my 13-year-old son Leo and me playing Mind Flex, an EEG-based game that we got for Christmas.

Source Code: BMIs in Sci-Fi

The BMI is our sci-fi obsession. For good reason.

A good brain-machine interface (BMI) makes everything possible. At least it's the key to good late-model science fiction. "The Matrix's" head plug, through which humans are fed their illusory digital worlds; "Avatar's" less invasive full-body tanning-salon connections and "Surrogate's" EEG-like helmets, through which users connect to their robot proxies; "Inception's" contraption--who the hell knows where that thing plugged in, but it plugged in somewhere;"Eternal Sunshine of the Spotless Mind's" read-write fMRI-like device that could locate and erase memories.  All were functional in-out ports to the human brain and so keys to either a) "freeing" the mind from the "constraints" of the body, or b) "enslaving" the mind (and its body) to the controllers of the BMI. Or, more often,  both.

A new absorbing and fun BMI-enabled movie, "Source Code," by "Moon" director Duncan Jones, and starring Jake Gyllenhaal, Michelle Monaghan, and Vera Farmiga, plays around with multi-verse theory and free will.

Gyllenhaal plays an army sergeant with an  I/O port in his brain that enables him to travel, via the (pretty much unexplained--"it's math"--) "source code," into the recent past to investigate a terrorist plot. Actually, he appears to be traveling through time, but is really traveling through memory. The train explosion that kills him over and over again has already taken place and everyone he meets --including love-interest Monagham--is already dead.  He's not supposed to keep the train from exploding--it's too late for that--but to find the perp and avert a bigger, future, nuclear attack.

 Like the Bill Murray character in  "Groundhog Day," Gyllenhaal has multiple chances to do the job. And like "Groundhog Day," each replay is slightly skewed depending on his perceptions and actions. And finally, like "Groundhog Day"--and like real life--the first  reruns are extravagantly spent getting a clue about what kind of world we're dealing with and why it matters. The rest are spent trying to exercise our wills and defy the tyranny of circumstance.

That sounds heavy, but it's a fun, tightly-directed movie, well acted by all three leads. And it's  romantic, which is something since the Gyllenhaal and Monaghan characters only have a couple of minutes on the train to work with. And, if you've got any geek in you--and you must  if you're reading this--the film's got a fresh parallel-universes theme that will either delight you or push your buttons, depending on your feelings about infinite inflation and multi-verse cosmological models.

It's also realistic in one important way. (Spoiler alert!) The Gyllenhaal character is, in the film's primary universe, actually a locked-in-syndrome paraplegic, a victim of a helicopter crash in Afghanistan; he doesn't know it, but he is "technically dead."  A portion of his brain is still vital enough, though, to plug into a BMI, sending his consciousness and body image temporarily into the memories of others. Okay, here's the realistic part: In our world, too, it is patients with disabilities who are having BMIs implanted to let them  control wheelchairs, prosthetic limbs, and computer cursors with their thoughts. 

Lest you hope (or fear!) just any old port into the brain will function as a USB-like device enabling all kinds of brain apps, it's key to note that reading directional command signals from the motor cortex (which neuroscientist can already do) is a far cry from importing or exporting anything like a complex thought, belief, or memory. The best scientific understanding of what  constitutes thoughts, say, is so elementary today that the reality of importing or exporting them from the brain via computer (BMI) is a long way off. Just how long off, though, and just how we might prepare for that day, are important  questions worthy of as much scientific, philosophical, ethical, and cinematic attention as we can throw their way.