Information Capacity of EEG: Theoretical and Computational Limits of Recoverable Neural Information

Fuente: arXiv
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Main Author: Rao, Ishir
Format: Preprint
Published: 2025
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author Rao, Ishir
author_facet Rao, Ishir
contents Electroencephalography (EEG) is widely used to study human brain dynamics, yet its quantitative information capacity remains unclear. Here, we combine information theory and synthetic forward modeling to estimate the mutual information between latent cortical sources and EEG recordings. Using Gaussian-channel theory and empirical simulations, we find that scalp EEG conveys only tens of bits per sample about low-dimensional neural activity. Information saturates with approximately 64-128 electrodes and scales logarithmically with signal-to-noise ratio (SNR). Linear decoders capture nearly all variance that is linearly recoverable, but the mutual information they recover remains far below the analytic channel capacity, indicating that measurement physics - not algorithmic complexity - is the dominant limitation. These results outline the intrinsic ceiling on how much structure about brain state or thought content can be inferred from EEG.
format Preprint
id arxiv_https___arxiv_org_abs_2510_17841
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Information Capacity of EEG: Theoretical and Computational Limits of Recoverable Neural Information
Rao, Ishir
Information Theory
Neurons and Cognition
Electroencephalography (EEG) is widely used to study human brain dynamics, yet its quantitative information capacity remains unclear. Here, we combine information theory and synthetic forward modeling to estimate the mutual information between latent cortical sources and EEG recordings. Using Gaussian-channel theory and empirical simulations, we find that scalp EEG conveys only tens of bits per sample about low-dimensional neural activity. Information saturates with approximately 64-128 electrodes and scales logarithmically with signal-to-noise ratio (SNR). Linear decoders capture nearly all variance that is linearly recoverable, but the mutual information they recover remains far below the analytic channel capacity, indicating that measurement physics - not algorithmic complexity - is the dominant limitation. These results outline the intrinsic ceiling on how much structure about brain state or thought content can be inferred from EEG.
title Information Capacity of EEG: Theoretical and Computational Limits of Recoverable Neural Information
topic Information Theory
Neurons and Cognition
url https://arxiv.org/abs/2510.17841