“…Brain activity can be characterized by various signal modalities, such as invasive ElectroCorticoGraphy (ECoG) (Miller et al, 2010 ; Hiremath et al, 2015 ), non-invasive electroencephalogram (EEG) (Lazarou et al, 2018 ), the functional Magnetic Resonance Imaging (fMRI) (Cohen et al, 2014 ), and the functional Near-Infrared Spectroscopy (fNIRS) (Naseer and Hong, 2015 ). Due to its manageability, easy capture, high time resolution and relative cost effectiveness, the EEG signal has been widely adopted for substantial BCI applications, such as remote quadcopter control (Lin and Jiang, 2015 ), motion rehabilitation (Xu et al, 2011 ; Zhao et al, 2016 ), biometric authentication (Palaniappan, 2008 ), and emotions prediction (Padilla-Buritica et al, 2016 ). Currently, the electrophysiological brain patterns used in EEG-based BCI systems are mainly Steady-State Visual Evoked Potentials (SSVEPs) (Chen et al, 2015 ; Zhang et al, 2015 ; Zhao et al, 2016 ; Nakanishi et al, 2018 ), P300 (Cavrini et al, 2016 ), sensorimotor rhythms (SMRs) (Yuan and He, 2014 ; He et al, 2015 ), and motion-related cortical potential (MRCP, one kind of a slow cortical potential) (Karimi et al, 2017 ).…”