title: Three cases of feature correlation in an electrocorticographic BCI.
abstract: Three human subjects participated in a closed-loop brain computer interface cursor control experiment mediated by implanted subdural electrocorticographic arrays. The paradigm consisted of several stages: baseline recording, hand and tongue motor tasks as the basis for feature selection, two closed-loop one-dimensional feedback experiments with each of these features, and a two-dimensional feedback experiment using both of the features simultaneously. The two selected features were simple channel and frequency band combinations associated with change during hand and tongue movement. Inter-feature correlation and cross-correlation between features during different epochs of each task were quantified for each stage of the experiment. Our anecdotal, three subject, result suggests that while high correlation between horizontal and vertical control signal can initially preclude successful two-dimensional cursor control, a feedback-based learning strategy can be successfully employed by the subject to overcome this limitation and progressively decorrelate these control signals.
authors.affiliation: Dept. of Physics, University of Washington, Seattle, WA, USA. kjmiller@gmail.com
authors.forename: Kai J
authors.initials: KJ
authors.lastname: Miller
authors.forename: Timothy
authors.initials: T
authors.lastname: Blakely
authors.forename: Gerwin
authors.initials: G
authors.lastname: Schalk
authors.forename: Marcel
authors.initials: M
authors.lastname: den Nijs
authors.forename: Rajesh P N
authors.initials: RP
authors.lastname: Rao
authors.forename: Jeffrey G
authors.initials: JG
authors.lastname: Ojemann
mesh_terms: D000293:Adolescent; D000328:Adult; D000465:Algorithms; D004562:Electrocardiography / Q000379:methods*; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000502:physiology*; D010363:Pattern Recognition, Automated / Q000379:methods*; D013223:Statistics as Topic; D013647:Task Performance and Analysis; D014584:User-Computer Interface