title: A subject-independent pattern-based Brain-Computer Interface.
abstract: While earlier Brain-Computer Interface (BCI) studies have mostly focused on modulating specific brain regions or signals, new developments in pattern classification of brain states are enabling real-time decoding and modulation of an entire functional network. The present study proposes a new method for real-time pattern classification and neurofeedback of brain states from electroencephalographic (EEG) signals. It involves the creation of a fused classification model based on the method of Common Spatial Patterns (CSPs) from data of several healthy individuals. The subject-independent model is then used to classify EEG data in real-time and provide feedback to new individuals. In a series of offline experiments involving training and testing of the classifier with individual data from 27 healthy subjects, a mean classification accuracy of 75.30% was achieved, demonstrating that the classification system at hand can reliably decode two types of imagery used in our experiments, i.e., happy emotional imagery and motor imagery. In a subsequent experiment it is shown that the classifier can be used to provide neurofeedback to new subjects, and that these subjects learn to "match" their brain pattern to that of the fused classification model in a few days of neurofeedback training. This finding can have important implications for future studies on neurofeedback and its clinical applications on neuropsychiatric disorders.
authors.affiliation: Institute of Medical Psychology and Behavioral Neurobiology, Medical Faculty, University of Tübingen Tübingen, Germany.
authors.forename: Andreas M
authors.initials: AM
authors.lastname: Ray
authors.affiliation: Institute of Medical Psychology and Behavioral Neurobiology, Medical Faculty, University of Tübingen Tübingen, Germany ; Institute for Medical and Biological Engineering, Schools of Engineering, Medicine and Biology, Pontificia Universidad Católica de Chile Santiago de Chile, Chile ; Department of Psychiatry and Section of Neuroscience, School of Medicine, Pontificia Universidad Católica de Chile Santiago de Chile, Chile.
authors.forename: Ranganatha
authors.initials: R
authors.lastname: Sitaram
authors.affiliation: Institute of Medical Psychology and Behavioral Neurobiology, Medical Faculty, University of Tübingen Tübingen, Germany ; Graduate School of Neural and Behavioral Sciences, University of Tübingen Tübingen, Germany.
authors.forename: Mohit
authors.initials: M
authors.lastname: Rana
authors.affiliation: Institut de Recherche en Sciences Psychologiques, Université Catholique de Louvain Louvain-la-Neuve, Belgium.
authors.forename: Emanuele
authors.initials: E
authors.lastname: Pasqualotto
authors.affiliation: Institute of Medical Psychology and Behavioral Neurobiology, Medical Faculty, University of Tübingen Tübingen, Germany.
authors.forename: Korhan
authors.initials: K
authors.lastname: Buyukturkoglu
authors.affiliation: Neural and Biomedical Technology Department, Institute for Infocomm Research Singapore, Singapore.
authors.forename: Cuntai
authors.initials: C
authors.lastname: Guan
authors.affiliation: Neural and Biomedical Technology Department, Institute for Infocomm Research Singapore, Singapore.
authors.forename: Kai-Keng
authors.initials: KK
authors.lastname: Ang
authors.affiliation: Department of Electrical Engineering and Biomedical Imaging Center, Pontificia Universidad Católica de Chile Santiago, Chile.
authors.forename: Cristián
authors.initials: C
authors.lastname: Tejos
authors.affiliation: División de Neurociencia, Centro de Investigación en Complejidad Social, Facultad de Gobierno, Universidad del Desarrollo Santiago, Chile ; Unidad de Imágenes Avanzadas, Clínica Alemana, Universidad del Desarrollo Santiago, Chile.
authors.forename: Francisco
authors.initials: F
authors.lastname: Zamorano
authors.affiliation: Departamento de Psiquiatría, Centro Interdisciplinario de Neurociencia, Escuela de Medicina, Pontificia Universidad Católica de Chile Santiago, Chile.
authors.forename: Francisco
authors.initials: F
authors.lastname: Aboitiz
authors.affiliation: Institute of Medical Psychology and Behavioral Neurobiology, Medical Faculty, University of Tübingen Tübingen, Germany ; Ospedale San Camillo, Istituto di Ricovero e Cura a Carattere Scientifico Venezia, Italy.
authors.forename: Niels
authors.initials: N
authors.lastname: Birbaumer
authors.affiliation: Institute of Medical Psychology and Behavioral Neurobiology, Medical Faculty, University of Tübingen Tübingen, Germany ; Departamento de Psiquiatría, Centro Interdisciplinario de Neurociencia, Escuela de Medicina, Pontificia Universidad Católica de Chile Santiago, Chile.
authors.forename: Sergio
authors.initials: S
authors.lastname: Ruiz
keywords: BCI; common spatial patterns; emotion imagery; neurofeedback; subject-independent classification