Brain-Computer Interface (BCI) is a cutting-edge bio-intelligent technology that bypasses the transmission pathways of human muscles and peripheral nerves to enable direct information interaction between the human brain and external devices. Its core principle is to collect electrical signals from the activity of human brain neurons, decode and convert them through algorithms to generate control commands for devices, and realize two-way information communication between humans and machines. According to the degree of clinical intervention, BCIs are divided into four categories: non-invasive, semi-invasive, invasive and interventional. Each type has distinct technical features, advantages and drawbacks.
Non-invasive BCIs collect electroencephalogram signals via external scalp electrodes and represent the most basic civilian technology. Their advantages include complete non-invasiveness, convenient operation, low cost and reusability with a wide range of applications. However, their signals are susceptible to interference from the scalp and hair, resulting in low signal-to-noise ratio and limited accuracy. They can only execute simple command interactions and cannot support precise fine control.
Semi-invasive BCIs use minimally invasive surgery to place electrodes outside the dura mater. This technology avoids scalp signal interference and greatly improves signal accuracy and stability with relatively controllable surgical trauma. The downside is that minimally invasive craniotomy is still required, carrying certain surgical risks. Long-term implantation may cause adhesion of brain tissues and limit service life.
Invasive BCIs require electrodes to be implanted directly inside the cerebral cortex. Among the four types, they deliver the highest signal accuracy and fastest response speed, supporting complex and precise human-machine control. Their disadvantages are severe trauma and high surgical risks, and they may trigger brain inflammation, immune rejection and other problems, leading to extremely high barriers for clinical application.
Interventional BCIs are an emerging minimally invasive BCI technology. Electrodes are implanted through vascular catheters without craniotomy, achieving minimal trauma while balancing high precision and safety. Its shortcoming lies in immature research and development. Vascular adaptability and long-term implantation stability still need verification, and large-scale application has not been realized. The four types of BCIs each have pros and cons and can adapt to different application scenarios as complementary technologies.
