Brain-Computer Interface Technology: Neuralink, Neural Prosthetics, Medical Applications, and Ethical Challenges
BCI basic principles: record electrical activity of brain neurons (action potentials/spike trains), decode signals via machine learning into control commands (controlling robotic arms, computer cursors, or speech synthesizers), or input stimulation signals to the brain (e.g., deep brain stimulation DBS for Parkinson’s disease).
## Invasive vs. Non-Invasive BCIs
**Invasive BCI** (cortical microelectrode implants) provides highest spatial resolution and signal quality but carries surgical risk and long-term biocompatibility challenges. Milestone: BrainGate consortium (Brown University) implanted the Utah Array in motor cortex from 2004, enabling tetraplegic patients to control computer cursors and robotic arms by thought; 2023 *Nature* paper: paralyzed patients achieved ~62 words/minute natural speech synthesis via cortical recording + speech decoder.
**Neuralink** (Elon Musk) completed its first human implant in 2024, with reports showing the subject could control a computer cursor by thought. Neuralink’s distinctive approach: flexible polymer threads (vs. rigid silicon) and fully automated surgical robot.
**Non-invasive BCI** (EEG, fNIRS): high safety but poor signal quality (skull attenuates and disperses signals), mainly for simple intent detection (e.g., P300 speller for letter-by-letter communication for locked-in syndrome patients).
## Neuroethics Challenges
Core ethical questions: **Cognitive Enhancement** fair distribution — if BCI can enhance memory or attention in normal individuals, who can afford it? **Neural Privacy** — brain data is the most intimate personal information; how to prevent commercial or governmental misuse? **Identity and Agency** — when the brain is “enhanced” or “modified” via external algorithms, where are the boundaries of “self”? The [Neurorights Foundation (Rafael Yuste)](https://neurorights.org/) is working to incorporate neural rights (neural data control, cognitive liberty, mental integrity) into international human rights frameworks.
