The idea of connecting a human brain directly to a computer has been a staple of science fiction for decades — Films from the Future explores it through Ghost in the Shell and Transcendence. What has changed since 2018 is that this is no longer purely a research enterprise. Multiple companies are racing to turn brain-computer interfaces into commercial products, and the first human trials of implanted devices are underway.
The book's Brain-Computer Interfaces page covered the science of direct neural connections. Since then, the field has split into three distinct approaches, each with different risk profiles, capabilities, and ethical implications.
Invasive implants: Neuralink, founded by Elon Musk, has developed a coin-sized chip implanted directly into the brain through a surgical procedure performed by a custom-built robot. The device uses arrays of ultra-thin electrodes threaded into brain tissue to record neural activity. In 2024, Neuralink implanted its first device in a human patient, who was subsequently able to control a computer cursor with thought alone. The approach offers the highest signal quality but carries the most surgical risk.
Endovascular interfaces: Synchron has taken a fundamentally different path. Its stentrode is delivered through the blood vessels — inserted via the jugular vein and guided to a blood vessel adjacent to the motor cortex, eliminating the need for open brain surgery. Synchron reached human trials before Neuralink and has demonstrated that patients with severe paralysis can use the device to control digital devices. The signal quality is lower than direct implants, but the surgical risk is dramatically reduced.
Non-invasive wearables: Companies like Kernel and the former NextMind (acquired by Snap) have developed headsets that read brain activity from outside the skull using various sensing technologies. These offer the lowest risk and easiest adoption but currently provide far less detailed neural data. They are most useful for detecting broad mental states rather than precise intentions.
DARPA and other military research agencies continue to invest heavily in BCI technology for applications ranging from enhanced communication to direct neural control of weapons systems.
The book's frameworks converge on this technology with particular force. Informed Consent takes on new dimensions when the device is inside your brain: what does it mean to consent to a technology that could, in principle, read your thoughts? What data is collected? Who owns it? What happens when the company that made your brain implant goes bankrupt or is acquired?
The Human Dignity question — explored through Ghost in the Shell's Major Kusanagi, whose identity is inseparable from her cybernetic body — becomes increasingly practical. If a brain-computer interface changes how you think, process information, or relate to the world, at what point does the technology become part of who you are? See At what point does upgrading a human become creating a different kind of human?
Corporate Responsibility is also central. These are commercial products being developed by companies with investors, revenue targets, and competitive pressures. The same incentives that push companies to move fast and break things in software become alarming when the product is inside someone's skull.