• Neuralink is preparing to give a second trial patient their implant in June.
• This time, the implant will be inserted deeper into the brain to avoid electrode retraction.
• Nearly all of the electrodes of the first patient’s implant retracted from the brain tissue days after the surgery, losing functionality.

Unfortunately for Noland Arbaugh, a week after the very first surgery to insert the Neuralink implant into his brain, 85 percent of the electrode-bearing threads of the implant – the probes that recognise electrical signals from the brain – retracted.

This meant that he could only use 15 percent of the electrodes, which he managed to do successfully after Neuralink adjusted certain algorithms to be more sensitive to brain stimuli. There is no guarantee, however, that the rest of the electrodes will remain implanted given enough time.

“I was on such a high and then to be brought down that low. It was very, very hard,” Arbaugh told The Wall Street Journal (paywall). The implant allowed Arbaugh, who is paralysed, to use social media and play videogames with his mind.

Neuralink is now hoping to take what it learned from the first patient and apply it to the second, who will reportedly receive their own Neuralink brain implant in June. The Elon Musk-founded company has already been granted approval by the US Food and Drug Administration (FDA).

This time, the Wall Street Journal report adds, Neuralink is planning to insert the electrodes deeper into the second patient’s brain tissue than they did with the first, in an effort to counteract possible tendril retraction.

Instead of the previous 3mm to 5mm insertion with Arbaugh, the second patient will have the implant’s electrode-bearing threads inserted to depths of 8mm into their brain. The surgical process is quite graphic, and involves what is essentially a giant sewing machine needle inserting the electrical probes through the cranium.

There is still, however, no guarantee that the electrodes will not retract as the brain tissue and cells react to the foreign presence. It is the body’s natural process to cast out bodies it does not recognise on its own, this includes machines like the Neuralink.

This is supposedly why these first patients are considered human trials. These are tests to gauge the effectiveness of the implant and its safety. If the electrodes continue to retract, Neuralink may have to return to the drawing board. Which would be a shame, because the technology, for the time the implant is sitting still, does work.

“I cried,” Arbaugh said in an interview, referring to the time when he began to lose functionality with the implant.

“I thought that I had just gotten to, you know, scratch the surface of this amazing technology, and then it was all going to be taken away,” he said.

“But it only took me a few days to really recover from that and realize that everything I’ve done up to that point was going to benefit everyone who came after me.”