The future of neural engineering looks promising for use in rehabilitation and treatment with a number of companies racing to human trials with neural implants that use micron–scale threads to process, stimulate and transmit signals back to a computer or wireless device that controls activity.
Neuralink, a company that Elon Musk is reported to have sunk $100 million into, has created a sealed implant they call the “Link.” Each thread inside the Link, which contain electrodes, is so fine and flexible that they cannot be inserted by human hand. Instead, neurosurgeons work with a custom robotic system to reliably insert the threads exactly where needed. A compact, inductive charger wirelessly connects the implant to charge the battery from the outside. Musk called it “a Fitbit in your brain” in his webcast with Gertrude the pig.
To date, only a few devices are approved for recording or stimulating the human brain, including one for treating Parkinson’s called deep brain stimulation (DBS) with leads that have 4-8 electrodes. Other devices are instrumental in the detection and disruption of seizures. They are designed to modulate the activity of whole brain areas, not to transfer information to and from the brain, so they only need a small number of electrodes (less than 10) and are about 800 times larger than what new devices are proposing. Elsewhere in clinical trials, other devices are using BMI movement control or sensory restoration with no more than a few hundred electrodes placed on the surface of the brain or in fixed arrays of single rigid electrodes.
Musk’s Link uses more electrodes and flexible threads that are individually placed to avoid blood vessels and to best cover the specific brain region of interest. He claims that the Link offers over 1,024 channels of information from the brain, the ability to perform real-time spike detection on every channel, and send data wirelessly.
A cure for blindness?
While Musk’s team was showing off the Link they had implanted in Gertrude the pig, Australian scientists from Monash University claimed research success with sheep who were implanted with a bionic vision system called “Gennaris.” The Aussies are reportedly ahead of Musk as they move to human trials of their bionic eye, which links to an implanted vision chip made of 9×9 millimetre tiles. Their hope is to cure blindness.
The implanted chip works with a camera, fitted into custom headgear, that captures what is in the surrounding scene. It then forwards what it “sees” to a vision processor where data is extracted and wirelessly flowed, via complex circuitry, into electrical pulses that stimulate the brain. Many people who are clinically blind have damaged optic nerves. These prevent signals from being transmitted from the retina to the vision centre of the brain. Amazingly, the vision system can bypass this damage, making it possible to treat many conditions that currently have treatment limitations.
Ramp up of manufacturing and distribution of the implant, which researchers say could soon be used to cure other conditions, including paralysis, is waiting for funding.