Scientists at the University of Bath have created artificial neurons that, in a world’s first, behave just like the real thing and could be used to cure diseases like heart failure and Alzheimer’s.
Creating artificial neurons that respond realistically has been a big goal and challenge for the scientific community for decades. 
But the university says its research team has cracked it with a combination of maths, computation and microchip design, successfully reproducing – in what has been described as a paradigm-changing project – the electrical properties of biological neurons onto semiconductor chips, pictured.
Critically the artificial neurons not only behave just like biological neurons but need just one billionth the power of a microprocessor, making them ideally suited for use in medical implants and other bio-electronic devices.
The team, led by the University of Bath, included researchers from the universities of Bristol, Zurich and Auckland. Their research has been published this week in the journal Nature Communications.
It opens up the possibility of curing conditions where neurons are not working properly, have had their processes severed, as in spinal cord injury, or have died.
Artificial neurons could repair diseased bio-circuits by replicating their healthy function and responding adequately to biological feedback to restore bodily function.
In heart failure, for example, neurons in the base of the brain do not respond properly to nervous system feedback, they in turn do not send the right signals to the heart, which then does not pump as hard as it should.
However, developing artificial neurons has been an immense challenge because of issues of complex biology and hard-to-predict neuronal responses.
The researchers successfully modelled and derived equations to explain how neurons respond to electrical stimuli from other nerves. This is incredibly complicated as responses are ‘non-linear’ – a signal that becomes twice as strong should not necessarily elicit twice as big a reaction and might be three times bigger.
They then designed silicon chips that accurately modelled biological ion channels before proving that their silicon neurons precisely mimicked real, living neurons responding to a range of stimulations.
The researchers accurately replicated the complete dynamics of hippocampal neurons and respiratory neurons from rats, under a wide range of stimuli.
The project was let by Prof Alain Nogaret, from the University of Bath Department of Physics, pictured, below left, with research associate Kamal Abu Hassan. He said: “Until now neurons have been like black boxes – but we have managed to open the black box and peer inside. Our work is paradigm changing because it provides a robust method to reproduce the electrical properties of real neurons in minute detail. 
“But it’s wider than that, because our neurons only need 140 nanoWatts of power. That’s a billionth the power requirement of a microprocessor, which other attempts to make synthetic neurons have used. This makes the neurons well suited for bio-electronic implants to treat chronic diseases.
“For example, we’re developing smart pacemakers that won’t just stimulate the heart to pump at a steady rate but use these neurons to respond in real time to demands placed on the heart – which is what happens naturally in a healthy heart.”
Other possible applications could be in the treatment of conditions like Alzheimer’s and neuronal degenerative diseases more generally.
Prof Nogaret said their approach combined several breakthroughs.
“We can very accurately estimate the precise parameters that control any neurons behaviour with high certainty. We have created physical models of the hardware and demonstrated its ability to successfully mimic the behaviour of real living neurons.
“Our third breakthrough is the versatility of our model which allows for the inclusion of different types and functions of a range of complex mammalian neurons.”
Prof Giacomo Indiveri from the University of Zurich and ETF Zurich, a co-author on the study, added: “This work opens new horizons for neuromorphic chip design thanks to its unique approach to identifying crucial analogue circuit parameters.”
Another co-author, Prof Julian Paton, a physiologist at the University of Auckland and the University of Bristol, said: “Replicating the response of respiratory neurons in bioelectronics that can be miniaturised and implanted is very exciting and opens up enormous opportunities for smarter medical devices that drive towards personalised medicine approaches to a range of diseases and disabilities.”
The study was funded by a European Union Horizon 2020 Future Emerging Technologies Programme grant and a doctoral studentship funded by the Engineering and Physical Sciences Research Council (ESPRC).
