ABSTRACT
A brain–computer interface (BCI) is a system that provides a direct pathway between the brain and an external device, allowing people to act on the world without moving any muscle. In order to do so, the BCI needs access to the central nervous system and, in particular, to the brain. Invasive BCI systems are those that are implanted directly into the brain of the user [1,2]. They allow the detection of cleaner signals, but they need surgery to be installed. On the other hand, in noninvasive BCIs, the insight into the neural processes is most frequently given by electroencephalography (EEG) systems that record the electric activity of the brain from the scalp of the user [3–15]. EEG-based BCIs have several advantages: they are easy to use, are compact, and provide a very good time resolution. Thanks to these, several applications have been suggested in the last decades for EEG-based BCIs.
