neurofeedback

Neurofeedback shows you a live, moment-to-moment readout of one of your own brain signals — say, a bar that rises and falls with a particular rhythm — so you can watch what your brain is doing in real time. Normally that activity is completely hidden from you; turning it into something you can see or hear is the whole point.

Once the signal is visible, you can try, through practice, to nudge it in a chosen direction: calm a certain rhythm, or push up a marker of attention. You are not given step-by-step instructions; instead, you experiment, and the feedback gradually teaches your brain what works, much like learning to wiggle your ears by watching a mirror.

It is a training-oriented cousin of control BCIs. Where a control BCI reads your brain to operate a device, neurofeedback aims the loop back at you — the goal is to change the brain signal itself, leaning on the brain's capacity to reshape itself with practice.