Weight-freezing: A motor imagery inspired regularization approach for EEG classification

Weight-freezing: A motor imagery inspired regularization approach for EEG classification

Abstract

In the realm of EEG decoding, enhancing the performance of artificial neural networks (ANNs) carries significant potential. This study introduces a novel motor imagery inspired approach, termed “Weight-Freezing”. The concept of Weight-Freezing revolves around the idea of reducing certain neurons’ influence on the decision-making process for a specific EEG task by freezing specific weights in the fully connected layer during the backpropagation process. This is actualized through the use of a mask matrix and a threshold to determine the proportion of weights to be frozen. Moreover, by setting the penalty factor to zero, Weight-Freezing can realize sparse connections in networks with a fully connected layer as the classifier. Through experiments involving three distinct ANN architectures and three widely recognized EEG datasets — BCI4-2A, BCI4-2B, and High-Gamma — we validated the effectiveness of Weight-Freezing. Our method significantly outperformed state-of-the-art classification accuracy across all examined datasets, achieving 84.9%, 86.5%, and 96.9% accuracy (averaged across all participants) for BCI4-2A, BCI4-2B, and High-Gamma, respectively. Supplementary control experiments offer insights into performance differences pre and post Weight-Freezing implementation and scrutinize the influence of the threshold in the Weight-Freezing process. Our study underscores the superior efficacy of Weight-Freezing compared to traditional fully connected layers for EEG classification tasks. With its proven effectiveness, this innovative approach holds substantial promise for contributing to future strides in EEG decoding research.

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Authors
  • Miao, Zhengqing
  • Zhao, Meirong
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Shortfacts
Category
Journal Paper
Divisions
Neuroinformatics
Subjects
Programmiermethodik
Kuenstliche Intelligenz
Angewandte Informatik
Journal or Publication Title
Biomedical Signal Processing and Control
ISSN
1746-8094
Date
7 October 2024
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