intracortical recording

Intracortical recording uses tiny electrodes that go inside the cortex, sitting among the neurons themselves rather than resting on the surface. From this close, an electrode can hear individual neurons fire — the brain's sharpest, most basic signals — along with the blended hum of cells nearby. If scalp EEG is listening from outside the stadium, this is sitting in the stands among the fans, hearing single voices.

This is the highest-fidelity way to read the brain: it captures the firing of specific neurons in real time, which is exactly the detail needed to control a robotic arm or a cursor smoothly. It is the foundation of fully implanted brain–computer interfaces, where decoding depends on knowing what individual cells are doing.

Its great cost is invasiveness. The electrodes must be surgically pushed into living brain tissue, which carries real risk, and the body's healing response can gradually wrap the electrodes in scar tissue and dim the signal over months or years. Making implants that stay clear and reliable for a long time is one of the field's central challenges.