Bidirectional BCI

A brain–computer interface that possesses both a read channel, which decodes neural activity to drive an external effector, and a write channel, which delivers stimulation to return information to the nervous system, ideally operating at the same time. The defining feature is that the two directions are coupled: what is written depends on and informs what is being read.

The paradigmatic application is restoring the sensorimotor loop in paralysis, reading motor cortex to move a robotic or reanimated limb while writing to somatosensory cortex to return touch, so that action and its sensory consequences are reunited. Bidirectionality is what distinguishes such a system from open-loop stimulation, in which stimulation is scheduled or triggered without depending on decoded neural state.