an artificial synapse has been created that can change everything
I remember being struck by the idea of a positronic brain from the novels and stories of Isaac Asimov. Unfortunately, despite scientific advances over the past decades, there is nothing similar today. Not only the human brain, but also animals, turned out to be too complex for it to be possible to artificially create something like that. Nevertheless, there has been some progress in this direction. Details under the cut.
What are the achievements?
Just the other day, a joint team of scientists, consisting of both theoretical physicists and experimentalists, managed to create an artificial synapse. It is worth recalling that a synapse (Greek σύναψις, from συνάπτειν – connection, connection) is the place of contact between two neurons or a neuron and the effector cell receiving the signal. It serves to transmit a nerve impulse between two cells, and during synaptic transmission the amplitude and frequency of the signal can be adjusted.
And this is a serious project, the results of which were published in the journal Proceedings of the National Academy of Sciences (PNAS). According to the creators of the synapse, it is proof that a system located in approximately the same environment as the human brain can process very complex information.
The successes of scientists are not yet very large-scale. All that was possible to do was to create an analogue of a neuron with a size of 150×200 microns. And this analogue was able to transmit information through ions in an aqueous solution. The developers do not call the synapse a synapse; in their work they use a different name – ionic memristor.
From the memristor to the creation of any significant model of the brain – like before the Moon. But there are still some achievements. A memristor is a microscopic conical channel. Inside is an aqueous solution of salt. Accordingly, if you apply electricity to it, a current arises and the concentration of ions changes. In this case, the conductivity of the channel itself varies depending on the intensity or duration of the pulse.
The length of the channel largely occurs in the time it takes for the concentration changes to disappear. Accordingly, technology can be used to store and process data – much the same as what happens with our brain.
According to the creators of the artificial synapse, the discovery is quite important, since it makes it possible to use just a saline solution to operate an artificial “brain.” In the near future, scientists plan to actively develop the project, for example, to create new types of computer systems based on it – very economical and at the same time productive.
What can an artificial synapse do?
It consists of two soft polymer electrodes. They separated by a gutterfilled with electrolyte. Accordingly, it itself plays an important role as a synaptic cleft that separates communicating neurons in the brain. If cells are placed on an electrode, neurotransmitters released by the cells can react with the electrode, producing ions.
They, in turn, gradually move to the second electrode through the trough and modulate the conductive state of the electrode. Some changes persist, which allows scientists to talk about the system performing a learning process that is also implemented in nature.
By expert opinion, as a result, approximately the same learning occurs as in a normal brain. This method is very energy efficient. The fact is that calculations and memory storage are implemented during one action. But if we draw an analogy with digital data, the situation is different, because data in computer systems is first processed and then moved to storage.
It may well be that the new development will become the basis for the creation of highly efficient and energy-saving computer systems, significantly surpassing existing technologies in this direction.
What's next?
If development is improved, a new type of computing system may emerge. The fact is that the brain is extremely energy efficient, and scientists from all over the world are trying to model its operation. Perhaps sooner or later this will be possible, but it is clear that in this case it will be necessary to use a water-salt solution, which is still unacceptable in modern PCs.
New models will be able to be functionally similar to the brain using the same synapses from the article as the main technology. After all, they play the main role in memorization, changing the configuration and connections between neurons. However, the creation of a more or less complex brain is still a long way off. The average person has about 100 billion neurons, which are connected by axons and dendrites.
The main advantage of “biological computers,” which may sooner or later be created, is the parallel solution of a large number of problems. And the main role here is played by synapses, which change not only the configuration, but also the connections between neurons.
It is worth noting that scientists at different times tried to create something similar, but most did not succeed. I would like to hope that the new development will speed up the creation of fast and energy-efficient devices.
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