Mind Control

Unifying algorithm for neural prosthetics will help convert brain signals into action.

In July 2006, a paper in Nature described how a paralyzed man with a chip implanted in his brain used his mind to move a computer cursor and a robotic arm. The chip is one of the most successful ­examples to date of a neural prosthetic. Such devices pick up neural signals from a part of the brain involved in a given ac­tivity, such as the neurons in the motor cortex that fire as a person imagines moving a computer mouse by hand. Then they interpret those signals and direct a physical action accordingly–say, moving a cursor to the left.

Lakshminarayan Srinivasan’s algorithms should speed development of new neural prosthetics.

Neural prosthetics promise to empower people with neurodegenerative diseases and ­spinal-­cord injuries. But because they can involve many combinations of brain regions and hardware, each new prototype has needed its own software. Designing new algorithms from scratch slows development, says ­Lakshminarayan Srinivasan, SM ‘03, PhD ‘06, a neurosurgery research fellow at the Massachusetts General Hospital and a medical student in the Harvard-MIT Division of Health Sciences and Technology. So Srinivasan is developing general algorithms that could lead to software compatible with all such devices.

Technologies for detecting brain ac­tivity include functional magnetic resonance imaging (fMRI), electroencephalography (EEG), and functional near-infrared spectroscopy–each of which generates different kinds of data. Output devices might include TVs, computers, or robotic arms, each of which has different user commands.

Srinivasan’s algorithms apply to any combination of devices because they operate at a higher level of abstraction. Instead of working just with EEG inputs reflecting electrical activity or MRI inputs showing blood flow in the brain, the algorithms treat all neural activity as either continuous or binary (a simple on/off switch) and translate it into continuous or discrete commands. (In driving a car, for example, gradually pressing the accelerator is a continuous command; shifting gears is a discrete command.)

Srinivasan says these algorithms should help researchers develop new neural prosthetics and quickly repair any problems that crop up.

Become an MIT Technology Review Insider for in-depth analysis and unparalleled perspective.

Subscribe today

Uh oh–you've read all of your free articles for this month.

Insider Premium
$179.95/yr US PRICE

Want more award-winning journalism? Subscribe and become an Insider.
  • Insider Premium {! insider.prices.premium !}*

    {! insider.display.menuOptionsLabel !}

    Our award winning magazine, unlimited access to our story archive, special discounts to MIT Technology Review Events, and exclusive content.

    See details+

    What's Included

    Bimonthly magazine delivery and unlimited 24/7 access to MIT Technology Review’s website

    The Download: our daily newsletter of what's important in technology and innovation

    Access to the magazine PDF archive—thousands of articles going back to 1899 at your fingertips

    Special discounts to select partner offerings

    Discount to MIT Technology Review events

    Ad-free web experience

    First Look: exclusive early access to important stories, before they’re available to anyone else

    Insider Conversations: listen in on in-depth calls between our editors and today’s thought leaders

  • Insider Plus {! insider.prices.plus !}* Best Value

    {! insider.display.menuOptionsLabel !}

    Everything included in Insider Basic, plus ad-free web experience, select discounts to partner offerings and MIT Technology Review events

    See details+

    What's Included

    Bimonthly magazine delivery and unlimited 24/7 access to MIT Technology Review’s website

    The Download: our daily newsletter of what's important in technology and innovation

    Access to the magazine PDF archive—thousands of articles going back to 1899 at your fingertips

    Special discounts to select partner offerings

    Discount to MIT Technology Review events

    Ad-free web experience

  • Insider Basic {! insider.prices.basic !}*

    {! insider.display.menuOptionsLabel !}

    Six issues of our award winning magazine and daily delivery of The Download, our newsletter of what’s important in technology and innovation.

    See details+

    What's Included

    Bimonthly magazine delivery and unlimited 24/7 access to MIT Technology Review’s website

    The Download: our daily newsletter of what's important in technology and innovation

/
You've read all of your free articles this month. This is your last free article this month. You've read of free articles this month. or  for unlimited online access.