BrainOmni: A Brain Foundation Model for Unified EEG and MEG Signals

Fuente: arXiv
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Main Authors: Xiao, Qinfan, Cui, Ziyun, Zhang, Chi, Chen, Siqi, Wu, Wen, Thwaites, Andrew, Woolgar, Alexandra, Zhou, Bowen, Zhang, Chao
Format: Preprint
Published: 2025
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author Xiao, Qinfan
Cui, Ziyun
Zhang, Chi
Chen, Siqi
Wu, Wen
Thwaites, Andrew
Woolgar, Alexandra
Zhou, Bowen
Zhang, Chao
author_facet Xiao, Qinfan
Cui, Ziyun
Zhang, Chi
Chen, Siqi
Wu, Wen
Thwaites, Andrew
Woolgar, Alexandra
Zhou, Bowen
Zhang, Chao
contents Electroencephalography (EEG) and magnetoencephalography (MEG) measure neural activity non-invasively by capturing electromagnetic fields generated by dendritic currents. Although rooted in the same biophysics, EEG and MEG exhibit distinct signal patterns, further complicated by variations in sensor configurations across modalities and recording devices. Existing approaches typically rely on separate, modality- and dataset-specific models, which limits the performance and cross-domain scalability. This paper proposes BrainOmni, the first brain foundation model that generalises across heterogeneous EEG and MEG recordings. To unify diverse data sources, we introduce BrainTokenizer,the first tokenizer that quantises spatiotemporal brain activity into discrete representations. Central to BrainTokenizer is a novel Sensor Encoder that encodes sensor properties such as spatial layout, orientation, and type, enabling compatibility across devices and modalities. Building upon the discrete representations, BrainOmni learns unified semantic embeddings of brain signals by self-supervised pretraining. To the best of our knowledge, it is the first foundation model to support both EEG and MEG signals, as well as the first to incorporate large-scale MEG pretraining. A total of 1,997 hours of EEG and 656 hours of MEG data are curated and standardised from publicly available sources for pretraining. Experiments show that BrainOmni outperforms both existing foundation models and state-of-the-art task-specific models on a range of downstream tasks. It also demonstrates strong generalisation to unseen EEG and MEG devices. Further analysis reveals that joint EEG-MEG (EMEG) training yields consistent improvements across both modalities. Code and checkpoints are publicly available at https://github.com/OpenTSLab/BrainOmni.
format Preprint
id arxiv_https___arxiv_org_abs_2505_18185
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle BrainOmni: A Brain Foundation Model for Unified EEG and MEG Signals
Xiao, Qinfan
Cui, Ziyun
Zhang, Chi
Chen, Siqi
Wu, Wen
Thwaites, Andrew
Woolgar, Alexandra
Zhou, Bowen
Zhang, Chao
Signal Processing
Machine Learning
Electroencephalography (EEG) and magnetoencephalography (MEG) measure neural activity non-invasively by capturing electromagnetic fields generated by dendritic currents. Although rooted in the same biophysics, EEG and MEG exhibit distinct signal patterns, further complicated by variations in sensor configurations across modalities and recording devices. Existing approaches typically rely on separate, modality- and dataset-specific models, which limits the performance and cross-domain scalability. This paper proposes BrainOmni, the first brain foundation model that generalises across heterogeneous EEG and MEG recordings. To unify diverse data sources, we introduce BrainTokenizer,the first tokenizer that quantises spatiotemporal brain activity into discrete representations. Central to BrainTokenizer is a novel Sensor Encoder that encodes sensor properties such as spatial layout, orientation, and type, enabling compatibility across devices and modalities. Building upon the discrete representations, BrainOmni learns unified semantic embeddings of brain signals by self-supervised pretraining. To the best of our knowledge, it is the first foundation model to support both EEG and MEG signals, as well as the first to incorporate large-scale MEG pretraining. A total of 1,997 hours of EEG and 656 hours of MEG data are curated and standardised from publicly available sources for pretraining. Experiments show that BrainOmni outperforms both existing foundation models and state-of-the-art task-specific models on a range of downstream tasks. It also demonstrates strong generalisation to unseen EEG and MEG devices. Further analysis reveals that joint EEG-MEG (EMEG) training yields consistent improvements across both modalities. Code and checkpoints are publicly available at https://github.com/OpenTSLab/BrainOmni.
title BrainOmni: A Brain Foundation Model for Unified EEG and MEG Signals
topic Signal Processing
Machine Learning
url https://arxiv.org/abs/2505.18185