The world of neuroprosthetics is an extraordinary and ground-breaking branch of neuroscience that is set to change the face of medicine as we currently understand it. Arguably the most successful form of neuroprosthetic that we have witnessed so far is the cochlear implant, which has been used since 2014 to restore hearing in people who have acquired deafness after learning how to speak (if you needed any reminder of the profound personal impact of these devices, watch Sarah Churman having her implant turned on for the first time). Put simply, a neuroprosthetic is defined as any prosthesis implanted in the nervous system that is able to improve or substitute the function of damaged brain matter, and this concept is currently being explored – with high degrees of success – to restore fundamental functions such as sight with artificial retinas, and the ability for paralyzed people to move robotic limbs with only thought. However, the most baffling form of neuroprosthetic currently in development is undoubtedly the memory implant, which could restore the ability for patients suffering from dementia, stroke or brain injury damage to create long-term memories.
Theodore Berger, a biomedical engineer and neuroscientist at the University of Southern California, is the architect of the ‘memory chip’ and, despite being originally slandered as “nuts” by his colleagues, has achieved remarkable successes with his neuroprosthetic and may prove to be one of the greatest pioneer scientists of our age. Berger’s ‘memory chip’ is otherwise recognized as a hippocampal implant, because it assumes the function of the hippocampus – the component of the human brain that encodes long-term memory from short-term memory. At its basis, the hippocampal implant works by mimicking the electrical pulses generated by neurons in the brain when memories are being formed and retrieved, which may well sound straightforward in theory – but with an average of 100 billion neurons in the human brain, this is a daunting piece of technology to create.
Berger and his team first established the theoretical success of such a device in humans by showing that they could restore long-term memory in rats. The team began by teaching the rats to press one of two levers in order to receive food, and captured the code of neurons that they believed to represent the memory of this learning. After drugging the rats to interfere with their long-term memory, the researchers demonstrated that they could use a pulse of the code to ensure that they picked the correct lever again. They were restoring memory with the push of a button and have shown equal success in primate trials.
However, while Berger and his team may have deciphered thousands of neuronal memory codes, the complexity of their mathematical equations and the coding process is laborious and may still be some way from fully restoring memory function in humans. Although Berger himself maintains, “The goal is to improve the quality of life for somebody who has a severe memory deficit. If I can give them the ability to form new long-term memories for half the conditions that most people live in, I’ll be happy as hell, and so will be most patients.”
Unsurprisingly, there has been a significant amount of interest in Berger’s work from investors, and he was recently funded to launch a start-up called Kernel to develop both the hippocampal implant as well as a neuroprosthesis, to detect and prevent seizures in epilepsy patients. In 2016, Berger began work to commercialize the ‘memory chip’ and is currently on the verge of trialling with human subjects. There are currently 5.4 million people suffering the neurodegenerative effects of Alzheimer’s in the US alone and for these patients, as well as those who have suffered strokes or traumatic brain injury that disrupted the ability to form long-term memory, Berger’s work represents an incredible step towards improving their lives and restoring normal brain function.