arXiv:2601.00973eess.IVeess.SP2026-01

从静息态fMRI推断脑区血流动力学差异,提升连接性分析准确性。

Learned Hemodynamic Coupling Inference in Resting-State Functional MRI

  • 通过边缘化神经信号,基于边际似然推断血流动力学耦合
  • 在真实与合成数据上均优于现有方法,提升连接性估计精度
  • 适用于脑功能成像研究者,尤其关注个体差异的神经科学领域

功能性磁共振成像(fMRI)通过随脑区和个体变化的血流动力学反应间接测量神经活动。忽略这种变异会偏差后续的连接性估计。此外,血流动力学参数本身可能成为重要的影像生物标志物。从静息态fMRI(rsfMRI)中估计空间异质的血流动力学是一个重要但具有挑战性的盲反问题,因为潜在神经活动与血流动力学耦合均未知。本文提出一种在皮层表面推断血流动力学耦合的方法。该方法通过边缘化潜在神经信号,基于由此产生的边际似然进行推断,避免了神经活动与血流动力学联合恢复的高不稳定性。为实现可扩展、高分辨率估计,采用深度神经网络结合条件归一化流来准确逼近这一难以计算的边际似然,同时利用定义在皮层表面的先验确保空间一致性,并支持稀疏表示。通过双重自助法量化血流动力学估计的不确定性。该方法在合成数据和真实fMRI数据集上进行了广泛验证,证明在血流动力学估计和下游连接性分析方面显著优于现有方法。

原文摘要 · Abstract (English)

Functional magnetic resonance imaging (fMRI) provides an indirect measurement of neuronal activity via hemodynamic responses that vary across brain regions and individuals. Ignoring this hemodynamic variability can bias downstream connectivity estimates. Furthermore, the hemodynamic parameters themselves may serve as important imaging biomarkers. Estimating spatially varying hemodynamics from resting-state fMRI (rsfMRI) is therefore an important but challenging blind inverse problem, since both the latent neural activity and the hemodynamic coupling are unknown. In this work, we propose a methodology for inferring hemodynamic coupling on the cortical surface from rsfMRI. Our approach avoids the highly unstable joint recovery of neural activity and hemodynamics by marginalizing out the latent neural signal and basing inference on the resulting marginal likelihood. To enable scalable, high-resolution estimation, we employ a deep neural network combined with conditional normalizing flows to accurately approximate this intractable marginal likelihood, while enforcing spatial coherence through priors defined on the cortical surface that admit sparse representations. Uncertainty in the hemodynamic estimates is quantified via a double-bootstrap procedure. The proposed approach is extensively validated using synthetic data and real fMRI datasets, demonstrating clear improvements over current methods for hemodynamic estimation and downstream connectivity analysis.

fMRI血流动力学连接性分析

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