Neuralink confirmed this week the successful implantation of its fourth human Telepathy patient — the first to also receive the company's newer N1.5 chip with the upgraded thread array. The patient, identified only as P4, is paralyzed from the neck down and demonstrated control of a robotic arm five days post-surgery.
The implant happened on April 18 at the Barrow Neurological Institute in Phoenix. P4 is the first patient to feed brain signals through Neuralink's new 1,536-electrode N1.5 chip — double the channel count of the original N1 used in patients P1 through P3.
What P4 can do already
In a video released by Neuralink yesterday, P4 demonstrated:
- **Robotic arm control** with 6 degrees of freedom — picking up a glass of water, drinking, returning it
- **Cursor control** at speeds rivaling P1's eight-month performance after only five days
- **Direct typing** by thinking words; current speed ~30 WPM, projected to climb past 60 WPM within 60 days
Elon Musk posted on X that P4's training "compressed five months of P1 progress into five days" — credit going to the new electrode density and an upgraded decoder built on top of Tesla's FSD neural network architecture.
The N1.5 upgrade
The new chip iteration brings three concrete improvements:
- **1,536 electrodes** (vs 1,024 in N1) across 64 polymer threads
- **Thinner threads**: 4 microns each (down from 5), reducing tissue scarring
- **On-chip decoder**: real-time signal processing without external compute, cutting latency from 23ms to 4ms
The R1 robot performed the surgical implantation autonomously, taking 23 minutes from craniotomy to wound closure.
Where this leads
Neuralink applied to the FDA in March for permission to expand Telepathy enrollment from 5 patients (current PRIME study) to 50 patients in the PRIME-2 study. Decision expected Q3 2026.
The company also confirmed P5 is scheduled for May 2026 — the first patient outside the United States, set for surgery at the Toronto Western Hospital.
If timelines hold, by year-end 2026 there will be 12-15 humans walking around with Neuralink chips talking to computers without touching them.
Sources
- Neuralink official update (April 25, 2026): PRIME study P4 implant successful
- Reuters (April 26, 2026): Neuralink fourth patient controls robotic arm
- Wall Street Journal (April 25, 2026): Neuralink N1.5 chip doubles electrode count
- Elon Musk X post (April 26, 2026)