arXiv:2511.00443cs.LGcs.AI2025-11被引 3

用解剖区域指导掩码,提升脑影像预训练模型的准确性和可解释性。

Region-Aware Reconstruction Strategy for Pre-training fMRI Foundation Model

  • 基于AAL3图谱选择性掩码脑区,而非随机遮蔽
  • 在ADHD-200数据集上分类准确率提升4.23%
  • 适用于需要可解释性的神经影像分析任务

神经影像领域基础模型的发展得益于大规模异构脑影像数据的可用性。自监督学习中的重建目标近年来展现出在多种功能磁共振(fMRI)下游任务中有效泛化的潜力。本研究探索了静息态fMRI基础模型的区域感知重建策略,超越传统随机区域掩码方法。我们引入基于自动解剖标注图谱(AAL3)的ROI引导掩码策略,直接应用于完整的4D fMRI体积,以选择性地掩码语义连贯的脑区进行自监督预训练。在包含973名受试者静息态fMRI扫描的ADHD-200数据集上,该方法相较常规随机掩码实现分类准确率提升4.23%,用于区分健康对照与注意缺陷多动障碍患者。区域级归因分析表明,边缘系统和小脑区域对重建保真度与模型表征贡献最大。结果表明,预训练阶段采用解剖区域掩码不仅能增强模型可解释性,还能生成更鲁棒、更具区分性的表征。未来工作将拓展至更多神经影像数据集,并开发基于区域感知重建目标的新损失函数,进一步提升基础模型在功能神经影像中的鲁棒性与可解释性。

原文摘要 · Abstract (English)

The emergence of foundation models in neuroimaging is driven by the increasing availability of large-scale and heterogeneous brain imaging datasets. Recent advances in self-supervised learning, particularly reconstruction-based objectives, have demonstrated strong potential for pretraining models that generalize effectively across diverse downstream functional MRI (fMRI) tasks. In this study, we explore region-aware reconstruction strategies for a foundation model in resting-state fMRI, moving beyond approaches that rely on random region masking. Specifically, we introduce an ROI-guided masking strategy using the Automated Anatomical Labelling Atlas (AAL3), applied directly to full 4D fMRI volumes to selectively mask semantically coherent brain regions during self-supervised pretraining. Using the ADHD-200 dataset comprising 973 subjects with resting-state fMRI scans, we show that our method achieves a 4.23% improvement in classification accuracy for distinguishing healthy controls from individuals diagnosed with ADHD, compared to conventional random masking. Region-level attribution analysis reveals that brain volumes within the limbic region and cerebellum contribute most significantly to reconstruction fidelity and model representation. Our results demonstrate that masking anatomical regions during model pretraining not only enhances interpretability but also yields more robust and discriminative representations. In future work, we plan to extend this approach by evaluating it on additional neuroimaging datasets, and developing new loss functions explicitly derived from region-aware reconstruction objectives. These directions aim to further improve the robustness and interpretability of foundation models for functional neuroimaging.

fMRI自监督学习可解释性基础模型

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