Visual evoked potentials for attentional gating in a brain-computer interface.

For synchronous brain-computer interface (BCI) paradigms tasks that utilize visual cues to direct the user, the neural signals extracted by the computer are representative of voluntary modulation as well as evoked responses. For these paradigms, the evoked potential is often overlooked as a source of artifact. In this paper, we put forth the hypothesis that cue priming, as a mechanism for attentional gating, is predictive of motor imagery performance, and thus a viable option for self-paced (asynchronous) BCI applications. We approximate attention by the amplitude features of visually evoked potentials (VEP)s found using two methods: trial matching to an average VEP template, and component matching to a VEP template defined using independent component analysis (ICA). Templates were used to rank trials that display high vs. low levels of fixation. Our results show that subject fixation, measured by VEP response, fails as a predictor of successful motor-imagery task completion. The implications for the BCI community and the possibilities for alternative cueing methods are given in the conclusions.