EEG-based recognition of activities and states involves the use of prior
neuroscience knowledge to generate quantitative EEG features, which may limit
BCI performance. Although neural network-based methods can effectively extract
features, they often encounter issues such as poor generalization across
datasets, high predicting volatility, and low model interpretability. Hence, we
propose a novel lightweight multi-dimensional attention network, called
LMDA-Net. By incorporating two novel attention modules designed specifically
for EEG signals, the channel attention module and the depth attention module,
LMDA-Net can effectively integrate features from multiple dimensions, resulting
in improved classification performance across various BCI tasks. LMDA-Net was
evaluated on four high-impact public datasets, including motor imagery (MI) and
P300-Speller paradigms, and was compared with other representative models. The
experimental results demonstrate that LMDA-Net outperforms other representative
methods in terms of classification accuracy and predicting volatility,
achieving the highest accuracy in all datasets within 300 training epochs.
Ablation experiments further confirm the effectiveness of the channel attention
module and the depth attention module. To facilitate an in-depth understanding
of the features extracted by LMDA-Net, we propose class-specific neural network
feature interpretability algorithms that are suitable for event-related
potentials (ERPs) and event-related desynchronization/synchronization
(ERD/ERS). By mapping the output of the specific layer of LMDA-Net to the time
or spatial domain through class activation maps, the resulting feature
visualizations can provide interpretable analysis and establish connections
with EEG time-spatial analysis in neuroscience. In summary, LMDA-Net shows
great potential as a general online decoding model for various EEG tasks.

提出了一种轻量级多维注意力网络 LMDA-Net，通过整合来自多个维度的特征，在各种 BCI 任务中实现了改进的分类性能，并且通过特定于类别的神经网络特征可解释性算法对其特征进行解释分析，展示出作为各种脑电任务的通用在线解码模型的巨大潜力。