Inside Neuralink's First Human Trial: The Science of Playing Chess With Your Mind

Imagine looking at a computer screen and moving the cursor simply by thinking about it. In early 2024, a 29-year-old paralyzed man made this a reality. By participating in Neuralink’s first human trial, he demonstrated how brain-computer interface technology can bypass spinal injuries and connect the human mind directly to digital devices.

The Breakthrough Moment: Chess via Telepathy

In March 2024, Neuralink broadcast a live video on the social media platform X. The video featured Noland Arbaugh, a 29-year-old man who lost all muscle control below his shoulders after a diving accident eight years prior. On the screen next to him, a computer mouse cursor glided across a digital chessboard, picking up pieces and moving them to new squares. Arbaugh was not using his hands, voice commands, or eye-tracking software. He was controlling the game entirely with his mind.

Arbaugh received the Neuralink implant in January 2024 as part of the company’s PRIME Study (Precise Robotically Implanted Brain-Computer Interface). The goal of this clinical trial is to test the safety and basic functionality of the device in humans. While the medical world has studied brain-computer interfaces for decades, Arbaugh’s fluid control of the cursor marked a massive leap forward in consumer-facing medical technology.

Beyond chess, Arbaugh quickly expanded his digital activities. He reported staying up until 6:00 AM playing the complex strategy game Civilization VI. Before the implant, he required a friend to physically move pieces for him or he had to use a slow mouth-operated stick. With the Neuralink device, he could play continuously for eight hours before the implant needed a wireless recharge.

How the Hardware Connects to the Brain

To understand how a person can play a video game with their thoughts, you have to look at the hardware hidden beneath the scalp. The Neuralink device used in this trial is called the N1 Implant. It is roughly the size of a large coin (about 23 millimeters wide and 8 millimeters thick). Surgeons remove a small circular piece of the patient’s skull and replace it exactly with the N1 Implant, meaning the device sits flush with the bone and remains completely invisible under the skin.

The true magic happens beneath the implant. The N1 features 64 ultra-flexible threads hanging down from the main computer chip. Across these 64 threads are 1,024 individual electrodes. These threads are inserted directly into the motor cortex, which is the exact region of the brain responsible for planning and executing voluntary movements.

Your brain naturally communicates using electrical signals called action potentials. Whenever you decide to move your hand, neurons in your motor cortex fire off these electrical spikes. In a paralyzed patient like Arbaugh, the brain still sends these signals, but the broken spinal cord stops the message from reaching the arms. The 1,024 electrodes in the N1 Implant act as tiny microphones. They listen to the electrical spikes firing in the motor cortex and transmit that data up to the chip.

Translating Thoughts to Digital Action

Recording the brain signals is only the first step. The N1 Implant must then translate those raw electrical spikes into something a standard computer can understand.

The implant processes the neural data and sends it wirelessly via Bluetooth to a custom Neuralink application on an external computer or smartphone. This app acts as a decoder. Through machine learning, the software learns which specific brain patterns correspond to Arbaugh’s intention to move his hand up, down, left, or right.

When Arbaugh imagines moving his hand to the left, the app instantly translates that specific electrical pattern into a command that moves the digital mouse to the left. The system is designed to mimic standard Bluetooth computer mice. Because it uses standard connection protocols, the patient can interface with regular off-the-shelf electronics like Apple MacBooks or standard Windows PCs without needing specialized operating systems.

The Role of the Surgical Robot

You might wonder how doctors safely insert 64 delicate wires into a living human brain. The short answer is they do not. The threads attached to the N1 Implant are roughly 14 microns wide, which is significantly thinner than a human hair. They are far too fragile for a human surgeon to handle with tweezers.

To solve this, Neuralink developed a specialized surgical robot called the R1. During the surgery, human doctors perform the initial skull incision, but the R1 robot takes over to insert the threads. The robot uses advanced optics to view the surface of the brain, actively mapping out the network of tiny blood vessels on the brain’s surface.

By pinpointing the exact locations of these vessels, the R1 robot can shoot the flexible threads into the brain tissue while avoiding the veins. This precise targeting minimizes bleeding and reduces scar tissue formation, which is vital because excess scar tissue can muffle the electrical signals the electrodes are trying to read.

Hurdles and Algorithm Adjustments

The first human trial has not been perfectly smooth. In May 2024, Neuralink published a blog post detailing an unexpected mechanical issue with Arbaugh’s implant. In the weeks following the surgery, several of the tiny threads naturally retracted and pulled out of his brain tissue.

Because fewer electrodes were touching the brain, the system captured less data. Arbaugh noticed his cursor control became sluggish and less accurate.

Instead of performing a dangerous second surgery to push the threads back in, Neuralink engineers addressed the problem through software. They updated the recording algorithm to be highly sensitive to the remaining electrodes. They also improved the techniques used to translate those remaining signals into cursor movements. According to Neuralink, these software adjustments fully restored Arbaugh’s cursor speed and actually pushed his control metrics higher than his initial post-surgery baseline.

Expanding the Trial: The Second Patient

Following the lessons learned from Arbaugh, Neuralink moved forward with a second patient in August 2024. A patient named Alex, who lost control of his limbs following a spinal cord injury, received the N1 Implant. To prevent the thread retraction issue seen in the first surgery, the surgical team took steps to reduce air pockets under the skull and placed the threads deeper into the tissue.

Alex’s results showed rapid success. Within minutes of connecting the device to his computer, he was controlling the cursor. On his second day with the implant, Alex used complex computer-aided design (CAD) software called Fusion 360 to design a custom 3D-printed mount for his Neuralink charger. He also began playing the fast-paced competitive shooter game Counter-Strike 2, using his mind to aim while using a customized mouth-controller to handle the character’s movement.

These milestones highlight the primary goal of the PRIME study. By proving that multiple paralyzed patients can safely and consistently control complex software, Neuralink is pushing brain-computer interfaces out of the laboratory and into practical daily life.

Frequently Asked Questions

How much does the Neuralink surgery cost? Currently, the Neuralink device is in the clinical trial phase, so patients like Noland Arbaugh and Alex do not pay for the procedure. However, early estimates from medical experts suggest that once the technology hits the commercial market, the surgical procedure could cost around $10,500, with total insurance billing potentially reaching $40,000.

Is the Neuralink implant safe? The United States Food and Drug Administration (FDA) granted Neuralink an Investigational Device Exemption in 2023, allowing the company to test the device in humans. While early results show no major health complications for the first two patients, the long-term safety regarding brain tissue health and device battery longevity is exactly what this multi-year clinical trial is trying to determine.

Who is eligible to get a Neuralink? Right now, Neuralink is only recruiting patients for its PRIME study. Eligible candidates must have limited or no ability to use both hands due to a cervical spinal cord injury or amyotrophic lateral sclerosis (ALS). They must also be at least 22 years old and have a reliable caregiver.