StableMind: Source-Free Cross-Subject fMRI Decoding with Regularized Adaptation

Fuente: arXiv
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Autores principales: Guo, Jintao, Wang, Lin, Li, Shumeng, Zhang, Jian, Zhou, Yulin, Cao, Luyang, Zheng, Hairong, Shi, Yinghuan
Formato: Preprint
Publicado: 2026
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author Guo, Jintao
Wang, Lin
Li, Shumeng
Zhang, Jian
Zhou, Yulin
Cao, Luyang
Zheng, Hairong
Shi, Yinghuan
author_facet Guo, Jintao
Wang, Lin
Li, Shumeng
Zhang, Jian
Zhou, Yulin
Cao, Luyang
Zheng, Hairong
Shi, Yinghuan
contents Existing cross-subject fMRI decoding methods typically train a model on multiple scanned subjects and then adapt it to a new subject using substantial paired fMRI-image data. However, in realistic scenarios, new-subject fMRI data are often limited due to costly data acquisition, and raw data from previous subjects may be inaccessible, leading existing methods to suffer performance degradation during new-subject adaptation. In this paper, we identify that this degradation stems from two key issues: brain-side instability caused by large subject differences in fMRI responses, and image-side supervision unreliability caused by fine-grained visual details that are not reliably supported by limited fMRI signals. To address these challenges, we propose StableMind, a regularized adaptation framework designed to improve brain-side representation stability and image-side supervision reliability. (1) To stabilize brain representations, StableMind reuses ridge projections from the pretrained model as adaptation priors to constrain limited-data new-subject adaptation, and applies Fourier-based feature-level brain augmentation to improve robustness to individual variability. (2) To improve image supervision reliability, StableMind introduces difficulty-aware image blur for brain-image alignment, reducing the influence of fine-grained visual details that are weakly supported by limited fMRI signals while preserving stable visual structure. Experiments on the Natural Scenes Dataset under a unified 1-hour adaptation protocol demonstrate that StableMind achieves 84.02% image retrieval accuracy and 81.66% brain retrieval accuracy averaged over four subjects, surpassing the state-of-the-art method by 5.71% brain retrieval accuracy with fewer trainable adaptation parameters. Our code is available at https://github.com/lingeringlight/StableMind.
format Preprint
id arxiv_https___arxiv_org_abs_2605_02586
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle StableMind: Source-Free Cross-Subject fMRI Decoding with Regularized Adaptation
Guo, Jintao
Wang, Lin
Li, Shumeng
Zhang, Jian
Zhou, Yulin
Cao, Luyang
Zheng, Hairong
Shi, Yinghuan
Computer Vision and Pattern Recognition
Existing cross-subject fMRI decoding methods typically train a model on multiple scanned subjects and then adapt it to a new subject using substantial paired fMRI-image data. However, in realistic scenarios, new-subject fMRI data are often limited due to costly data acquisition, and raw data from previous subjects may be inaccessible, leading existing methods to suffer performance degradation during new-subject adaptation. In this paper, we identify that this degradation stems from two key issues: brain-side instability caused by large subject differences in fMRI responses, and image-side supervision unreliability caused by fine-grained visual details that are not reliably supported by limited fMRI signals. To address these challenges, we propose StableMind, a regularized adaptation framework designed to improve brain-side representation stability and image-side supervision reliability. (1) To stabilize brain representations, StableMind reuses ridge projections from the pretrained model as adaptation priors to constrain limited-data new-subject adaptation, and applies Fourier-based feature-level brain augmentation to improve robustness to individual variability. (2) To improve image supervision reliability, StableMind introduces difficulty-aware image blur for brain-image alignment, reducing the influence of fine-grained visual details that are weakly supported by limited fMRI signals while preserving stable visual structure. Experiments on the Natural Scenes Dataset under a unified 1-hour adaptation protocol demonstrate that StableMind achieves 84.02% image retrieval accuracy and 81.66% brain retrieval accuracy averaged over four subjects, surpassing the state-of-the-art method by 5.71% brain retrieval accuracy with fewer trainable adaptation parameters. Our code is available at https://github.com/lingeringlight/StableMind.
title StableMind: Source-Free Cross-Subject fMRI Decoding with Regularized Adaptation
topic Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2605.02586