title: EEG oscillatory patterns and classification of sequential compound limb motor imagery.
abstract: BACKGROUND
  A number of studies have been done on movement imagination of motor sequences with a single limb. However, brain oscillatory patterns induced by movement imagination of motor sequences involving multiple limbs have not been reported in recent years. The goal of the present study was to verify the feasibility of application of motor sequences involving multiple limbs to brain-computer interface (BCI) systems based on motor imagery (MI). The changes of EEG patterns and the inter-influence between movements associated with the imagination of motor sequences were also investigated.
  
  
  METHODS
  The experiment, where 12 healthy subjects participated, involved one motor sequence with a single limb and three kinds of motor sequences with two or three limbs. The activity involved mental simulation, imagining playing drums with two conditions (60 and 30 beats per minute for the first and second conditions, respectively).
  
  
  RESULTS
  Movement imagination of different limbs in the sequence contributed to time-variant event-related desynchronization (ERD) patterns within both mu and beta rhythms, which was more obvious for the second condition compared with the first condition. The ERD values of left/right hand imagery with prior hand imagery were significantly larger than those with prior foot imagery, while the phase locking values (PLVs) between central electrodes and the mesial frontocentral electrode of non-initial movement were significantly larger than those of the initial movement during imagination of motor sequences for both conditions. Classification results showed that the power spectral density (PSD) based method outperformed the multi-class common spatial patterns (multi-CSP) based method: The highest accuracies were 82.86 % and 91.43 %, and the mean values were 65 % and 74.14 % for the first and second conditions, respectively.
  
  
  CONCLUSIONS
  This work implies that motor sequences involving multiple limbs can be utilized to build a multimodal classification paradigm in MI-based BCI systems, and that prior movement imagination can result in the changes of neural activities in motor areas during subsequent movement imagination in the process of limb switching.
authors.affiliation: Department of Biomedical Engineering, College of Precision Instruments and Optoelectronics Engineering, Tianjin University, Tianjin, China. yiweibo1987@163.com.|Tianjin Key Laboratory of Biomedical Detecting Techniques and Instruments, Tianjin University, Tianjin, China. yiweibo1987@163.com.
authors.forename: Weibo
authors.initials: W
authors.lastname: Yi
authors.affiliation: Department of Biomedical Engineering, College of Precision Instruments and Optoelectronics Engineering, Tianjin University, Tianjin, China. qiushuang@tju.edu.cn.|Tianjin Key Laboratory of Biomedical Detecting Techniques and Instruments, Tianjin University, Tianjin, China. qiushuang@tju.edu.cn.
authors.forename: Shuang
authors.initials: S
authors.lastname: Qiu
authors.affiliation: Department of Biomedical Engineering, College of Precision Instruments and Optoelectronics Engineering, Tianjin University, Tianjin, China. Flora_wk@tju.edu.cn.|Tianjin Key Laboratory of Biomedical Detecting Techniques and Instruments, Tianjin University, Tianjin, China. Flora_wk@tju.edu.cn.
authors.forename: Kun
authors.initials: K
authors.lastname: Wang
authors.affiliation: Department of Biomedical Engineering, College of Precision Instruments and Optoelectronics Engineering, Tianjin University, Tianjin, China. qhz@tju.edu.cn.|Tianjin Key Laboratory of Biomedical Detecting Techniques and Instruments, Tianjin University, Tianjin, China. qhz@tju.edu.cn.
authors.forename: Hongzhi
authors.initials: H
authors.lastname: Qi
authors.affiliation: Department of Biomedical Engineering, College of Precision Instruments and Optoelectronics Engineering, Tianjin University, Tianjin, China. heaven@tju.edu.cn.|Tianjin Key Laboratory of Biomedical Detecting Techniques and Instruments, Tianjin University, Tianjin, China. heaven@tju.edu.cn.
authors.forename: Feng
authors.initials: F
authors.lastname: He
authors.affiliation: Department of Biomedical Engineering, College of Precision Instruments and Optoelectronics Engineering, Tianjin University, Tianjin, China. zpzpa@vip.sina.com.|Tianjin Key Laboratory of Biomedical Detecting Techniques and Instruments, Tianjin University, Tianjin, China. zpzpa@vip.sina.com.
authors.forename: Peng
authors.initials: P
authors.lastname: Zhou
authors.affiliation: Department of Biomedical Engineering, College of Precision Instruments and Optoelectronics Engineering, Tianjin University, Tianjin, China. lxzhang@tju.edu.cn.|Tianjin Key Laboratory of Biomedical Detecting Techniques and Instruments, Tianjin University, Tianjin, China. lxzhang@tju.edu.cn.
authors.forename: Lixin
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of Biomedical Engineering, College of Precision Instruments and Optoelectronics Engineering, Tianjin University, Tianjin, China. richardming@tju.edu.cn.|Tianjin Key Laboratory of Biomedical Detecting Techniques and Instruments, Tianjin University, Tianjin, China. richardming@tju.edu.cn.
authors.forename: Dong
authors.initials: D
authors.lastname: Ming
mesh_terms: D000328:Adult; D001611:Beta Rhythm; D062207:Brain-Computer Interfaces; D004567:Electrodes, Implanted; D004569:Electroencephalography / Q000379:methods*; D058407:Electroencephalography Phase Synchronization; D005121:Extremities / Q000502:physiology*; D005260:Female; D005528:Foot / Q000502:physiology; D006225:Hand / Q000502:physiology; D006801:Humans; D007092:Imagination / Q000502:physiology*; D008297:Male; D009068:Movement / Q000502:physiology*; D011597:Psychomotor Performance; D060388:Support Vector Machine; D055815:Young Adult
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