Monday, December 15, 2014

Brain-Like Circuits Can Mimic Pavlov's Dogs

Originally published: Dec 15 2014 - 1:45pm, Inside Science News Service
By: Charles Q. Choi, Contributor

(Inside Science) -- Artificial electronic circuits that mimic the pathways connecting neurons in the brain can learn, unlearn and store memories, researchers have reported. These inventions could not only help researchers better understand how the brain works, but could also lead to advanced new computers.

Brains are the most powerful computers known. This is due in large part to their complexity — the human brain has roughly 100 billion neurons, with about one million billion connections known as synapses wiring them together.

Scientists have long strived to mimic the brain electronically using either software or hardware. However, current software simulations of the brain, such as the IBM Blue Gene project, require lots of energy as well as dozens of cabinets of computers, while conventional hardware imitations of the brain are limited by the lack of components that can adequately mimic the way synapses behave, said researcher Shriram Ramanathan, a materials scientist at Harvard University in Cambridge, Massachusetts.

Image credit: Singkham via shutterstock |

The way that synapses work underlies the ability of brains to learn. Synapses control the amount of electric charge transmitted from one neuron to another. The electrical conductivity of synapses can increase or decrease depending on how much they are stimulated, a property known as synaptic plasticity. Memories are encoded using collections of synapses of different strengths.

Conventional transistors cannot easily reproduce synaptic plasticity — for instance, they usually act more like on-off switches, going only either to 0 or 1, instead of ranging across a continuum of values as synapses do. Now Ramanathan and his colleagues have invented a new type of transistor that can mimic synaptic plasticity, developing systems that can learn, unlearn and store memories.

"This work represents a significant departure from traditional electronics," Ramanathan said.

The new device is made with films of samarium nickel oxide, or SNO for short. Unlike silicon and other conventional semiconductors used in electronics, SNO has a great range of electrical conductivities due to strong interactions between its atoms. When these materials are placed in contact with ionic liquids — fluids made up of both positively and negatively charged ions — applying positive or negative electric voltages to such coupled systems can respectively decrease or increase the long-term electrical conductivity of SNO.

"This is a rather new way of thinking about neural circuitry — it's creative and very clever," said materials chemist Eric Garfunkel at Rutgers University in Piscataway, New Jersey, who did not participate in this study.

The scientists then used their devices to conduct versions of Pavlov's famous experiments with dogs, in which canines learned to associate food with the ringing of a bell. The circuits could learn that two electrical stimuli are linked if they repeatedly came at the same time, and unlearn this association if these two stimuli stopped being coupled. The circuits could also store patterns of electrical signals they experienced, mimicking how the brain stores memories. The similarity of these devices to real synapses could help them serve as "an electronic platform to probe fundamental problems in neuroscience," Ramanathan said.

In addition, "in principle, it is possible to use these findings to construct analog cognitive devices that learn from interaction with their environment in a way similar to animals and humans," said neuromorphic computing researcher Michael Schmuker at the University of Sussex in England, who did not take part in this research. "The potential advantage over digital circuits, which are currently used for this task, may lie in lower power consumption."

Ramanathan cautioned this work is only a prototype meant to demonstrate proof of the concept.

"We need to advance this frontier significantly to get towards an actual brain-like entity that has orders of magnitude more connective elements," he said.

One key challenge is the speed of operation of such devices. "Electrons move very fast, but ions move relatively slow," Garfunkel said. Ramanathan suggested their devices could move roughly as fast as real synapses, "but it could be a challenge to get them to work at microprocessor speeds."

The scientists detailed their findings online Dec. 4 in the journal Physical Review Applied.

Charles Q. Choi is a freelance science writer based in New York City who has written for The New York Times, Scientific American, Wired, Science, Nature, and many other news outlets. He tweets at @cqchoi.


  1. In future, electronics circuit will replace human brain. But nowadays students can get all they need from paper writing services. Anyway, human brain always will be more powerful instrument than other.

  2. Thanks for the blog.Really thank you! Keep writing.

  3. Baggage really are trendy gear and additionally amongst the trendiest types of purses which usually are recognized for simply being useful and additionally for a spaciousness. louis vuitton replica This approach accommodating ladies handbag for females is useful for toting all of the must-haves and the best intended for succeed, class, jaunts and additionally some usages. replica louis vuitton Cup like simultaneously model and additionally truly useful accessories, however these are equally just the thing for travel around. replica louis vuitton Mostly baggage experience couple of short-term contains consequently they are attainable by means of shifting and additionally easily removed band. fake chanel Described experience huge contains that could be put into use like connectors. chanel replica They also have an excessive memory space efficiency to oblige a good number of any normal essential. A lot of baggage come from lgt and additionally big equipment who are intended for all the time functionality in addition to travel around handbags. You’re able to find your right from several various kinds:

  4. Its very useful if every one should follow this


  5. its really informative tutorial. Thank you for this tutorial .

  6. Peoples are giving really nice comments

  7. Beautiful post given by so many peoples. wjdkj

  8. The information's are useful for all the people

  9. Nice Post and all information's are used to everybody

  10. All the post are good and the people nice comments to giving all post


  11. its really informative tutorial. Thank you for this tutorial .

  12. Must be appreciated for the article.

  13. Really nice,everybody like All the Post


  14. its really informative tutorial. Thank you for this tutorial .

  15. Nice to read all post and more innovative

  16. its really informative tutorial. Thank you for this tutorial . babblein


  17. Its useful to every one and keep posting

  18. Articles are very nice…Nice comments too. gxshangsi

  19. Peoples are giving the wonderful thoughts for all comments


  20. The information which you people are said here are really good..!!!

  21. Very useful comments are posted and everybody like this

  22. This comment has been removed by the author.

  23. its really informative tutorial. Thank you for this tutorial .

  24. The information which you people are said here are really good..!!!