Virtual reality
Because BCI are a closed-loop systems, feedback is an important component. Various methods of providing feedback can inform the participant about success or failure of an intended act. Thus, feedback either supports reinforcement during the learning/training process or in controlling the application. In particular, the use of virtual reality (VR) has been proven to be an interesting and promising way to realize such feedback.
Several prototypes have enabled users to navigate in virtual scenes solely by means of their oscillatory cerebral activity, recorded on the scalp via EEG electrodes. Healthy participants were exploring virtual spaces (Leeb et al., 2007b,c; Scherer et al., 2008; Ron-Angevin et al., 2009), were manipulating virtual objects (Lecuyer et al., 2008), and a spinal-cord injured patient was controlling a wheelchair through a virtual street (Leeb et al., 2007a). Additionally, evoked potentials (P300, Bayliss, 2003; and SSVEPs, Lalor et al., 2005) have been used to control VR feedback as well. In these studies, BCI users who use immersive Virtual Environments (VEs) make fewer errors, report that BCIs are easier to learn and use, and state that they enjoy BCI use more (Leeb et al., 2006, 2007b; Ron-Angevin et al., 2009). These benefits may occur because VEs enhance vividness and mental effort, which may lead to more distinct brain patterns and improve pattern recognition performance. Nevertheless, VR technologies provide motivating, safe, and controlled conditions that enable improvement of BCI learning as well as the investigation of the brain responses and neural processes involved, meanwhile testing new virtual prototypes.