A computer that runs on salt and water

All it takes is a little water and salt for a human brain to run — a most basic formula that works. If one can figure out the math, they should be able to reproduce it artificially.

Science has long pondered how to build an artificial system that mirrors the functionality of the human brain. That lies at the center of iontronic neuromorphic computing, an emerging field that studies the ionic computing system that living organisms have.

For the very first time, scientists have taken a concrete step forward in making this theoretical possibility a reality. The key turned out to be the synapse in the brain that transmits signals between neurons which send commands to the body: talk, walk, eat, think. They built a tiny synapse measuring 150 by 200 micrometers.

A strand of human hair has a diameter of 100 micrometers, to give an example of how small this device is.

“We are effectively replicating neuronal behavior using a system that employs the same medium as the brain,” said Tim Kamsma, a PhD candidate at the Institute for Theoretical Physics and the Mathematical Institute of Utrecht University, who is also the lead author of the study.

An artificial synapse can mimic neuronic behavior

This artificial synapse known as an iontronic memristor functions as a microchannel filled with a solution of water and salt. Electric input affects the ions in this solution, which then mirrors the activity of neurons.

The length of this channel changes how long it takes for “concentration changes to dissipate.” Electric input changes the liquid’s ion concentration.

After all, neurons in the human brain also fire off electrical signals. That’s the basic system that these researchers sought to mirror.

“This suggests the possibility of tailoring channels to retain and process information for varying durations, again akin to the synaptic mechanisms observed in our brains,” Kamsma said.

Kamsma began this journey as a PhD student, studying artificial ion channels. Working with a research group in South Korea enabled him to put his theories into practice.

“It’s incredibly gratifying to witness the transition from theoretical conjecture to tangible real-world outcomes, ultimately resulting in these beautiful experimental results.”

One step closer to brain-like computers

Iontronic neuromorphic computing has only recently broken ground but is developing at a rapid pace. A computer better than the ones living organisms already have (brain) just doesn’t exist.

This idea does spin the mind into theoretical territory around the future of AI and even consciousness.

That aside, the study published around the artificial synapse marks a significant step forward for the future of computers.

“It represents a crucial advancement toward computers not only capable of mimicking the communication patterns of the human brain but also utilizing the same medium,” he said. “Perhaps this will ultimately pave the way for computing systems that replicate the extraordinary capabilities of the human brain more faithfully.”

The team published their results in the scientific journal Proceedings of the National Academy of Sciences.