用零样本模型预测脑活动并发现因果关系,效果媲美传统方法。
Prediction and Causality of functional MRI and synthetic signal using a Zero-Shot Time-Series Foundation Model
- 用基础模型直接预测fMRI时间序列,无需训练
- 零样本预测误差控制在0.55(健康人)和0.27(患者)
- 能更精准识别神经环路间的因果关系,适合脑科学初学者
时间序列预测与因果发现是神经科学的核心问题,预测脑活动并识别神经群体间因果关系有助于揭示认知与疾病机制。随着基础模型兴起,一个关键问题是:它们相比传统方法在脑信号预测与因果分析中表现如何,能否实现零样本应用?本文评估了一个基础模型在人类静息态功能磁共振成像(fMRI)数据上,对方向性相互作用的推断能力。传统方法多依赖维纳-格兰杰因果关系。我们测试了该模型在零样本与微调两种设置下的预测性能,并通过比较模型生成的类格兰杰估计与标准格兰杰因果关系,评估其因果推断能力。使用基于真实因果模型生成的合成时间序列进行验证,包括逻辑映射耦合与奥恩斯坦-乌伦贝克过程。结果表明,该基础模型在零样本条件下实现了具有竞争力的预测性能(对照组均方百分比误差为0.55,患者组为0.27)。尽管标准格兰杰因果未显示模型间显著差异,但基础模型在因果交互检测上更精确。总体表明,基础模型具备高泛化性、强零样本性能,适用于时间序列的预测与因果发现。
原文摘要 · Abstract (English)
Time-series forecasting and causal discovery are central in neuroscience, as predicting brain activity and identifying causal relationships between neural populations and circuits can shed light on the mechanisms underlying cognition and disease. With the rise of foundation models, an open question is how they compare to traditional methods for brain signal forecasting and causality analysis, and whether they can be applied in a zero-shot setting. In this work, we evaluate a foundation model against classical methods for inferring directional interactions from spontaneous brain activity measured with functional magnetic resonance imaging (fMRI) in humans. Traditional approaches often rely on Wiener-Granger causality. We tested the forecasting ability of the foundation model in both zero-shot and fine-tuned settings, and assessed causality by comparing Granger-like estimates from the model with standard Granger causality. We validated the approach using synthetic time series generated from ground-truth causal models, including logistic map coupling and Ornstein-Uhlenbeck processes. The foundation model achieved competitive zero-shot forecasting fMRI time series (mean absolute percentage error of 0.55 in controls and 0.27 in patients). Although standard Granger causality did not show clear quantitative differences between models, the foundation model provided a more precise detection of causal interactions. Overall, these findings suggest that foundation models offer versatility, strong zero-shot performance, and potential utility for forecasting and causal discovery in time-series data.
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