arXiv:2607.22262stat.MLcs.LG2026-07

提出可联合建模空间与时间动态的变分张量分解方法,提升多被试神经影像数据的结构解析能力。

Variational Low-rank Tensor Decomposition for Multisubject Spatiotemporal Data Analysis

论文配图:Variational Low-rank Tensor Decomposition for Multisubject Spatiotemporal Data Analysis
图 1 · 摘自论文原文
  • 结合生成模型与结构化先验,联合建模空间图谱与时间动态
  • 在真实功能磁共振数据上显著优于经典与概率分解方法
  • 适合处理具有复杂个体差异的多被试时空数据,如脑影像分析

多被试时空数据中共享结构与个体特异性结构的建模仍具挑战性,尤其在神经影像领域,空间和时间模式在不同被试间表现出丰富变异。现有矩阵与张量分解虽提供可解释分解,但依赖固定多线性结构或耦合方案,限制了对复杂变异的捕捉能力。本文提出一种时空变分张量分解(ST-VTD)框架,将张量因子生成模型与结构化先验结合,共同表示空间图谱与时间动态。空间因子通过受LL1启发的低秩正则化实现稀疏性约束,时间因子采用基于长短期记忆网络(LSTM)的可学习先验,支持灵活自适应的动力学建模。后验推断采用展开优化算法迭代的摊销变分方法,构建可解释且参数高效的架构。推理框架引入基于组独立成分分析的热启动策略,显著提升优化性能。在真实合成功能磁共振(fMRI)数据集上的实验表明,该方法在潜在因子恢复上显著优于代表性经典与概率分解基准。

原文摘要 · Abstract (English)

Modeling shared and subject-specific structure in multisubject spatiotemporal data remains challenging, particularly in neuroimaging, where both spatial and temporal patterns exhibit rich variability across subjects. Existing matrix and tensor decompositions provide interpretable factorizations, but rely on fixed multilinear structures or coupling schemes that may limit their flexibility in capturing complex variability. In this work, we introduce a spatiotemporal variational tensor decomposition (ST-VTD) framework that combines a tensor factorization generative model with structured priors to jointly represent spatial maps and temporal dynamics. Spatial factors are regularized to promote a low-rank structure inspired by the LL1 decomposition, while temporal factors are modeled using a learned Long short-term memory (LSTM)-based prior, enabling flexible and adaptive dynamics. Posterior inference is performed using an amortized variational formulation by unrolling iterations of an optimization algorithm, leading to an interpretable and parameter-efficient architecture. The proposed inference framework employs a warm-start strategy based on group independent component analysis, which we found to improve optimization performance. Experiments on a realistic synthetic functional MRI (fMRI) dataset demonstrate that the proposed approach significantly improves latent factor recovery compared with representative classical and probabilistic decomposition benchmarks.

张量分解神经影像时空建模变分推断

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