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Main Authors: Sukhbaatar, Jamiyan, Imamura, Satoshi, Tanaka, Toshihisa
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2605.24921
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author Sukhbaatar, Jamiyan
Imamura, Satoshi
Tanaka, Toshihisa
author_facet Sukhbaatar, Jamiyan
Imamura, Satoshi
Tanaka, Toshihisa
contents A central challenge in electroencephalography (EEG) foundation modeling is learning transferable representations across recordings with diverse tasks, montages, references, and spectral characteristics. Existing masked modeling approaches often rely on broadband continuous patches or a single discrete representation, which may underrepresent frequency-specific activity. This paper proposes BandVQ, a band-wise vector-quantized EEG foundation model that decomposes EEG into delta, theta, alpha, beta, and gamma bands, trains an independent VQ-VAE tokenizer for each band, and pretrains a shared Transformer encoder on the resulting discrete VQ code indices. The encoder uses masked code tokens, quantized absolute log-power tokens, channel and temporal embeddings, and metadata prefix tokens representing reference, band, task family, and phase. Region-based masking is also introduced to reduce the trivial reconstruction of spatially adjacent electrodes. The model is pretrained on 71 public EEG corpora comprising over 9,200 subjects and 357,000 single-channel hours and evaluated on six subject-independent classification datasets. Under the current evaluation setting, the proposed model achieves strong transfer performance, with the highest reported results on three cognitive tasks and competitive performance on three motor imagery tasks.
format Preprint
id arxiv_https___arxiv_org_abs_2605_24921
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle BandVQ: Band-Wise Vector-Quantized EEG Foundation Model
Sukhbaatar, Jamiyan
Imamura, Satoshi
Tanaka, Toshihisa
Machine Learning
A central challenge in electroencephalography (EEG) foundation modeling is learning transferable representations across recordings with diverse tasks, montages, references, and spectral characteristics. Existing masked modeling approaches often rely on broadband continuous patches or a single discrete representation, which may underrepresent frequency-specific activity. This paper proposes BandVQ, a band-wise vector-quantized EEG foundation model that decomposes EEG into delta, theta, alpha, beta, and gamma bands, trains an independent VQ-VAE tokenizer for each band, and pretrains a shared Transformer encoder on the resulting discrete VQ code indices. The encoder uses masked code tokens, quantized absolute log-power tokens, channel and temporal embeddings, and metadata prefix tokens representing reference, band, task family, and phase. Region-based masking is also introduced to reduce the trivial reconstruction of spatially adjacent electrodes. The model is pretrained on 71 public EEG corpora comprising over 9,200 subjects and 357,000 single-channel hours and evaluated on six subject-independent classification datasets. Under the current evaluation setting, the proposed model achieves strong transfer performance, with the highest reported results on three cognitive tasks and competitive performance on three motor imagery tasks.
title BandVQ: Band-Wise Vector-Quantized EEG Foundation Model
topic Machine Learning
url https://arxiv.org/abs/2605.24921