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Scientists have created key pieces of synthetic brain cells that can hold cellular “memories” for milliseconds. The achievement could one day lead to computers that function like the human brain.
These parts, which were used to model an artificial brain cell, use charged particles called ions to produce an electrical signal, in the same way that information is transferred between neurons in your brain.
Computers today can do amazing things, but this processing power comes at a high energy cost. On the other hand, the human brain is remarkably efficient, using roughly the energy in two bananas to do an entire day’s work. While the reasons for this efficiency aren’t entirely clear, scientists felt that if they could make a computer look more like the human brain, it would require much less power. Scientists are trying to replicate the brain’s biological machinery using the power of ions, the charged particles the brain relies on to produce electricity.
Related: In the brain: a photographic journey through time
Artificial neurons
In the new study, published in the journal Science on August 6, researchers at the National Center for Scientific Research in Paris, France, created a computer model of artificial neurons that could produce the same type of electrical signals that neurons use. to transfer information to the brain; by sending ions through thin water channels to mimic real ion channels, researchers could produce these electrical spikes. And now, they’ve even created a physical model incorporating these channels as part of ongoing unpublished research.
“To my knowledge, this is the first time that people [have done] this with ions, ”said study co-author Lydéric Bocquet, a physicist at the École normale supérieure.
On a finer level, the researchers created a system that mimics the process of generating action potentials – spikes in electrical activity generated by the neurons that are the basis of brain activity. To generate an action potential, a neuron begins to let in more positive ions, which are attracted to the negative ions inside the cell. Electric potential, or voltage across the cell membrane, causes gates on the cell called Voltage-Closed ion channels open, further increasing the charge before the cell peaks and returns to normal a few milliseconds later. The signal is then transmitted to other cells, allowing information to travel to the brain.
To mimic voltage-gated ion channels, the researchers modeled a thin layer of water between sheets of graphene, which are extremely thin sheets of carbon. The water layers in the simulations were one, two, or three molecules deep, which the researchers characterized as a near-two-dimensional slit. Bocquet said the researchers wanted to use this two-dimensional environment because the particles tend to react much more strongly in two dimensions than in three, and they exhibit different properties in two dimensions, which the researchers say could be useful for their experience.
“In physics, two dimensions are very strange,” said Bocquet. “So you expect new things to happen. “
By testing the model in a computer simulation, the researchers found that when they applied an electric field to the channel, the ions in the water formed worm-like structures. As the team applied a stronger electric field in the simulation, these structures would break down slowly enough to leave behind a “Memory, “or an index of the elongated configuration.
When the researchers performed a simulation linking two channels and other components to mimic the behavior of a neuron, they found that the model could generate spikes in electrical activity like action potentials, and that it ” remembered “coherent properties in two different states – one where ions conduct more electricity and one where they conduct less. In this simulation, the “memory” of the previous state of the ions lasted for a few milliseconds, about the same time it takes real neurons to produce an action potential and return to a state of rest. That’s long enough for ions, which typically operate on nanosecond or less time scales. In a real neuron, an action potential is equivalent to cellular memory in the neuron; our brain uses the opening and closing of ion channels to create this type of memory.
“We ultimately have a similar memory, but the reason for the phenomenon is very different,” said Bocquet.
Make a “souvenir”
The new model is a version of an electronic component called a memristor, or memory resistor, which has the unique property of retaining information from its history. But the existing memristors do not use liquid, unlike the brain.
“The typical memristors that I work with, and others in the literature, are solid-state memristors,” said Gina Adam, assistant professor of electrical and computer engineering at George Washington University, who did not participated in the study. This new research on creating fluid memristors is “very promising and very intriguing,” added Adam.
She also said that while practical brain-like computers are probably far away, this research could also help scientists better understand how the brain processes information and develop new theories of brain-like computing.
Since conducting this research with computer simulations, Bocquet says that he and collaborators at the University of Manchester in the UK brought their theory to life, using it to create an artificial synapse, the part of ‘a neuron that transmits electrical signals, and they started experimenting with it.
“It’s exciting because it’s a playground now,” Bocquet said. “We can actively explore these things.”
Originally posted on Live Science.
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