An international team of researchers has developed artificial neurons that could be implanted in the brain to repair the damage caused by Alzheimer’s disease and other neurodegenerative conditions.

The silicon chips, which behave like biological neurons, only need 140 nanoWatts of power. That’s one billionth of the power required by the microprocessors that have been used in other attempts to make synthetic neurons, making the silicon chips well-suited to being used as medical implants or inside other bioelectronic devices.

The artificial neurons are designed to respond to electrical signals from the nervous system, something which has been a major goal in medicine for decades. The devices could be used to repair diseased biocircuits by replicating their healthy function through responding to biological feedback. This could make it possible to cure conditions where neurons are either not working properly, have had their processes severed or have died.

The research was led by the University of Bath and featured collaborators from the Universities of Bristol, Zurich and Auckland.

Researchers modelled and derived equations to explain how neurons responded to electrical stimuli from other nerves. This was a highly complicated process as these responses are ‘non-linear’, meaning if a signal comes in twice as strong it won’t necessarily elicit twice as big a reaction – it could be three times as big, for example.

Once the equations were established, the team 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 stimuli in rats. They were able to accurately replicate the complete dynamics of hippocampal neurons and respiratory neurons from rats under a wide range of stimuli.

University of Bath physics professor Alain Nogaret 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.

“Our approach combines 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.”

The researchers are now working on developing smart pacemakers, which will go beyond stimulating the heart to pump at a steady rate but respond in real-time to demands placed on the heart.