First Transistor That Mimics Brain Synapse
French researchers have created what they claim is the first transistor to mimic the connections in the human brain. It could lead to neurology-inspired computers, as well as provide a means for connecting artificial devices to existing biological tissue.
Schematic diagram illustrating how the NOMFET (bottom)
mimics a synapse (top). In a synapse, voltage spikes
(blue triangles) are converted to a chemical signal (orange arrow),
which flows across a gap. Once across, the chemical stimulates
the creation of new voltage spikes.
(Courtesy: Dominique Vuillaume))
The team, which includes scientists from the CNRS (the French National Science Agency) and CEA (the French Atomic Energy Commission), began by adding gold nanoparticles to the interface between an insulating layer (gate dielectric) and an organic transistor made of pentacene. They fixed the nanoparticles, which were 5, 10 and 20 nm in diameter, into the source-drain channel of the device using surface chemistry techniques and finished the structure by covering it with a 35 nm thick film of pentacene. The resulting device is called a nanoparticle organic memory field-effect transistor or "NOMFET".
A biological synapse transforms a voltage spike (action potential) arriving from a pre-synaptic neuron into a discharge of chemical neurotransmitters that are then detected by a post-synaptic neuron. These are subsequently transformed into new spikes, leading to a succession of pulses that either become larger or diminish in size. This fundamental property of synaptic behaviour is known as short-term plasticity, which is related to a neural network's ability to learn. It is this plasticity that Vuillaume and colleagues have succeeded in mimicking.
In the NOMFET, the pre-synaptic signal is simply the pulse voltage applied to the device and the output signal is the drain current, explains Vuillaume. The holes – the charge carriers in the p-type organic semiconductor employed – are trapped in the nanoparticles and act like the neurotransmitters. A certain number of holes are trapped for each incoming spike voltage and in the absence of pulses, the holes escape in a matter of seconds
This time delay is carefully adjusted by the researchers by optimizing nanoparticle number and device geometry. "The output of the NOMFET is thus able to reproduce the deceasing or amplifying behaviour typical of a synapse depending on the frequency of spikes," said Vuillaume.
Science fiction fans recall that Isaac Asimov, in his short story Reason, wrote about a similar idea:
All that had been done in the mid 20th century on "calculating machines" had been upset by Robertson and his positronic brain paths. The miles of relays and photocells had given way to the spongy globe of platinum iridium about the size of the human brain.
(Read more about the positronic brain)
A few years later, Philip K. Dick had fun with the idea of a Nexus-6 brain unit in his 1968 novel Do Androids Dream of Electric Sheep:
The Nexus-6 did have two trillion constituents plus a choice within a range of ten million possible combinations of cerebral activity. In .45 of a second an android equipped with such a brain could assume any one of fourteen basic reaction-postures. Well, no intelligence test could trap such an andy. But then, intelligence tests hadn't trapped an andy in years, not since the primordial, crude varieties of the 1970's.
From Physics World via Next Big Future.
Scroll down for more stories in the same category. (Story submitted 2/1/2010)
Follow this kind of news @Technovelgy.
| Email | RSS | Blog It | Stumble | del.icio.us | Digg | Reddit |
you like to contribute a story tip?
Get the URL of the story, and the related sf author, and add
Comment/Join discussion ( 1 )
Related News Stories -
Eterni.me - To Skype With The Dead
'Nothing... left of Jeserac but a galaxy of electrons frozen in the heart of a crystal.'- Arthur C. Clarke, 1956.
Razer Project Valerie Laptop Unfurls
'A paper thin polycarbon screen unfurled silently...' - William Gibson, 1986.
Google Home Continues Implementation Of Pohl's Joymaker
'It is a transponder connecting you with the central computing facilities of the city in which you reside on a shared-time, self-programming basis.' - Frederik Pohl, 1966.
New Startup 'Improbable' To Model Our World
'A machine able literally to contain the Universe Itself...' - Stanislaw Lem, 1965.
Technovelgy (that's tech-novel-gee!)
is devoted to the creative science inventions and ideas of sf authors. Look for
the Invention Category that interests
you, the Glossary, the Invention
Timeline, or see what's New.
Keith Laumer's Bolo Autonomous Tanks Right On Schedule
'I cannot lie idle under attack.'
When Computers Develop Their Own Language, Will They Talk To Us?
'The curious absent look of a robot talking on the TBR circuits - the Talk Between Robots radio...'
LipNet Reads Lips - Until Disconnected, That Is
'We'd have to cut his higher brain functions... I'm not sure what [HAL} would think about that.'
Eterni.me - To Skype With The Dead
'Nothing... left of Jeserac but a galaxy of electrons frozen in the heart of a crystal.'
Wearable MRI Is Former Occulus/Facebook Exec's New Project
'Your cephalochromoscope... that you always turn on and play when you get home...'
Ford Stratasys Infinte Build 3D Printer
'He proudly indicated his Buick... Almost as good as the original it was printed from...'
The Space Suit As Personal Spaceship
'Darn clever, these suits...'
Dune Fans! Your God Emperor Is Ready
'If one held a sandtrout in the hand, smoothing it over your skin, it formed a living glove.'
Robot Strolls Field, Examines EVERY Plant
'The great machines that did the work ... required but a few dozen men to cultivate an entire county.'
Sweden Outlaws Drones
'An eye that could not only see, but fly, roam, travel at speeds and in directions to suit its operator...'
Wear Your Self-Powered Generator
'It's basically a micro-sandwich...'
TITAN-III Spider Robot Is WAY Too Quick (Video)
'My little friends can find you wherever you go!'
Bill Gates Suggests Tax On Robots
'A worker replaced by a nubot that 'appears or pretends to be human' had to be compensated...'
Handle, New Wheeled Hopping Robot
'the hopper sprang thirty feet into the air...'
Matrix Sentinel Ancestor, The Pipe Inspector Robot From Krakow
Watch out, Keanu!
Auto-Focus Smart Glasses Have Liquid Lenses
'Hufhuf oil held in static tension by an enclosing force field within a viewing tube...'
More SF in the News Stories
More Beyond Technovelgy science news stories