Exploring spatial-frequency-sequential relationships for motor imagery classification with recurrent neural network

Tian-Jian Luo, Chang-le Zhou, Fei Chao

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84 Citations (SciVal)
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Conventional methods of motor imagery brain computer interfaces (MI-BCIs) suffer from the limited number of samples and simplified features, so as to produce poor performances with spatial-frequency features and shallow classifiers.

Alternatively, this paper applies a deep recurrent neural network (RNN) with a sliding window cropping strategy (SWCS) to signal classification of MI-BCIs. The spatial-frequency features are first extracted by the filter bank common spatial pattern (FB-CSP) algorithm, and such features are cropped by the SWCS into time slices. By extracting spatial-frequency-sequential relationships, the cropped time slices are then fed into RNN for classification. In order to overcome the memory distractions, the commonly used gated recurrent unit (GRU) and long-short term memory (LSTM) unit are applied to the RNN architecture, and experimental results are used to determine which unit is more suitable for processing EEG signals.

Experimental results on common BCI benchmark datasets show that the spatial-frequency-sequential relationships outperform all other competing spatial-frequency methods. In particular, the proposed GRU-RNN architecture achieves the lowest misclassification rates on all BCI benchmark datasets.

By introducing spatial-frequency-sequential relationships with cropping time slice samples, the proposed method gives a novel way to construct and model high accuracy and robustness MI-BCIs based on limited trials of EEG signals.
Original languageEnglish
Article number344
JournalBMC Bioinformatics
Issue number1
Publication statusPublished - 29 Sept 2018


  • EEG signals classification
  • spatial-frequency-sequential relationships
  • deep recurrent neural networks
  • brain computer interface
  • Spatial-frequency-sequential relationships
  • Brain computer interface
  • Deep recurrent neural networks
  • Brain-Computer Interfaces
  • Neural Networks, Computer
  • Datasets as Topic
  • Humans
  • Databases, Genetic
  • Electroencephalography/classification
  • Support Vector Machine
  • Algorithms
  • Imagination/physiology
  • Signal Processing, Computer-Assisted


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