用静息态脑图生成任务态脑信号,提升临床研究数据可用性。
FM-fMRI: Event Conditioned Flow Matching for Rest-to-Task fMRI Time-Series Synthesis

- 基于事件条件的流匹配模型,从静息态fMRI生成任务态时间序列。
- 在人类连接组计划和自闭症队列上实现最优频谱与连通性一致性。
- 适合脑科学、临床神经影像等数据稀缺场景的研究者使用。
任务态功能性磁共振成像(fMRI)可直接反映任务诱发的神经动态,但其采集成本高且难以大规模获取,因此推动了从广泛可用的静息态fMRI(rsfMRI)进行静息到任务态合成的研究。本文提出FM-fMRI,一种事件条件流匹配模型,通过学习连续时间条件向量场,从个体的rsfMRI及任务事件信息生成任务相关脑区(ROI)时间序列。该方法支持基于常微分方程(ODE)的快速采样,并能灵活适应异构的任务事件时序。不同于仅追求逐点重建的优化目标,我们采用互补评估标准:考察时间与频谱结构、个体与群体层面的脑网络一致性以及分布对齐程度。在公开的人类连接组计划(HCP)和内部的BioPoint自闭症队列数据集上,FM-fMRI在频谱与连通性一致性和分布匹配方面均优于条件扩散模型、生成对抗网络(GANs)和变分自编码器(VAEs)基线模型。此外,我们利用该方法为BioPoint队列扩充任务态fMRI ROI时间序列,显著提升了自闭症分类性能,验证了其在数据有限的临床场景中的实际应用价值。代码将开源于GitHub。
原文摘要 · Abstract (English)
Task-based fMRI provides a direct readout of task-evoked neural dynamics, but it is expensive and difficult to acquire at scale, motivating rest-to-task synthesis from widely available resting-state fMRI (rsfMRI). We propose FM-fMRI, an event-conditioned flow-matching model that learns a continuous-time conditional vector field to generate task ROI time series from a subject's rsfMRI and the task event information. The formulation enables fast ODE-based sampling and flexible conditioning over heterogeneous event schedules. Rather than optimizing for pointwise reconstruction, we evaluated generated signals using complementary criteria that probe temporal and spectral structure, subject and group-level connectome consistency, and distributional alignment. On the public Human Connectome Project and internal BioPoint autism cohort, FM-fMRI achieves the strongest spectral and connectivity agreement and improved distribution-level matching over conditional diffusion, generative adversarial networks (GANs), and variational autoencoders (VAEs) baselines. Furthermore, we augment the BioPoint cohort by synthesizing task-fMRI ROI time series with our method, improving downstream autism classification and demonstrating practical utility in data-limited clinical settings. The code will be available on GitHub.
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