Brain–computer interface

Dummy unit illustrating the design of a BrainGate interface

A brain–computer interface (BCI), sometimes called a brain–machine interface (BMI), is a direct communication link between the brain's electrical activity and an external device, most commonly a computer or robotic limb. BCIs are often directed at researching, mapping, assisting, augmenting, or repairing human cognitive or sensory-motor functions. Due to the cortical plasticity of the brain, signals from implanted prostheses can, after adaptation, be handled by the brain like natural sensor or effector channels. They are often conceptualized as a human–machine interface that skips the intermediary of moving body parts (e.g. hands or feet). BCI implementations range from non-invasive (EEG, MEG, MRI) and partially invasive (ECoG and endovascular) to invasive (microelectrode array) based on how physically close electrodes are to brain tissue.

Research on BCIs began in the 1970s by Jacques Vidal at the University of California, Los Angeles (UCLA) under a grant from the National Science Foundation. This was followed by a contract from the Defense Advanced Research Projects Agency (DARPA) that prompted further research into the technology. Vidal's 1973 paper introduced the expression brain–computer interface into scientific literature. Following years of animal experimentation, the first neuroprosthetic devices were implanted in humans in the mid-1990s