DARPA's Revolutionizing Prosthetics program aims to develop
technologies that can restore a near-natural sense of touch.
A prosthetic hand that is connected directly to the brain successfully
enabled a paralyzed man to "feel" again, according to researchers at
the Defense Advanced Research Projects Agency (DARPA).
The 28-year-old male, who suffered a
spinal cord
injury and has been paralyzed for more than a decade, was able to control a
robotic hand with his brain and reported being able to sense physical
sensations.
DARPA researchers attached electrodes to the man's sensory cortex — the area
of the brain responsible for identifying tactile sensations, such as pressure.
Electrodes were also placed on the patient's motor cortex, the part of the
brain that directs body movements.
Wires were run directly from the electrodes to the mechanical hand, which
was developed by the Johns Hopkins University Applied Physics Laboratory (APL)
in Laurel, Maryland. Using this connection, the man could control the robotic
hand's movements using the same types of thoughts, or neural connections, that
the brain uses to move a hand normally. In addition, because the prosthetic
hand was connected to the sensory cortex, the patient could
sense
when the hand was being touched, even when he was blindfolded.
DARPA officials announced the milestone during the agency's three-day
"Wait, What? Technology Forum," held last week in St. Louis.
The research is part of DARPA's Revolutionizing Prosthetics program, which
aims to develop a prosthetic that can not only be controlled by sending signals
for the brain, but can also sense precisely what those devices are touching.
"Prosthetic limbs that can be controlled by thoughts are showing great
promise," DARPA program manager Justin Sanchez
said in a statement,
"but without feedback from signals traveling back to the brain it can be
difficult to achieve the level of control needed to perform precise movements.
By wiring a sense of touch from a mechanical hand directly into the brain, this
shows the potential for seamless bio-technological restoration of near-natural
function."
In addition to this technology, DARPA reported preliminary findings from the
agency's
Restoring
Active Memory (RAM) program, which is a dedicated to augmenting memory
formation and recall in people suffering from memory loss.
DARPA has tested the program's first few dozen volunteers, who had neurological
problems unrelated to memory loss, agency officials said. These volunteers had
small electrode arrays placed in brain regions known to be involved in the
formation of declarative memory, or simple memory used to recall lists, as well
as in regions involved in spatial memory and navigation. These electrodes are
giving scientists the ability to "read" the processes involved in
memory formation and retrieval, and are even offering insights into when a
volunteer is about to make an error in recall.
According to their initial results, it is possible to read and interpret
these key signals in memory processing and even
improve
memory by providing targeted electrical stimulation to the brain, DARPA
officials said.
"We still have a lot to learn about how the human brain encodes
declarative memory," Sanchez said, "but these early experiments are
clarifying issues such as these and suggest there is great potential to help
people with certain kinds of memory deficits."
DARPA says the technologies being developed in the Revolutionizing
Prosthetics and Restoring Active Memory programs hold great potential for
improving brain function.
"As the technology of these fully implantable devices improves, and as
we learn more about how to stimulate the brain ever more precisely to achieve
the most therapeutic effects, I believe we are going to gain a critical
capacity to help our wounded warriors and others who today suffer from
intractable neurological problems," Sanchez said.