arXiv:2411.02949cs.LGmath.DS2024-11NeurIPS被引 14

用新算法从短时fMRI数据重建脑动力系统,突破信号滤波限制。

A scalable generative model for dynamical system reconstruction from neuroimaging data

  • 基于控制理论改进训练方法,解决信号历史依赖导致的解码不可逆问题
  • 仅用短时BOLD数据即可还原系统状态空间几何与长期动态特性
  • 模型维度和滤波长度扩展性极佳,适合大规模神经动力建模

从观测时间序列中数据驱动地推断生成动力系统的机制,在机器学习与自然科学中日益重要。在神经科学中,此类方法有望摆脱依赖生物物理原理的手工建模,实现个体间脑动力差异的自动化推断。近期针对动力系统重构(DSR)的隐状态模型(SSM)训练技术突破,使即使在短时间序列下也能恢复系统本身及其几何结构(如吸引子)和长期统计不变量。这些方法基于控制理论思想,如现代教师强制(TF)变体,确保训练中梯度传播稳定。然而,当前方法无法直接应用于观测值依赖于先前全部状态历史的信号类型——这在神经科学(及生理学)中普遍存在。典型例子包括功能磁共振成像(fMRI)中的血氧水平依赖(BOLD)信号或钙成像数据。这类信号使SSM解码器非可逆,而此前基于TF的方法要求可逆性。本文利用近期在训练SSM方面的控制技术成功经验,提出一种新算法,解决了该难题,并在模型维度与滤波长度上表现出卓越扩展性。我们在短时BOLD时间序列上验证了其高效重建动力系统的能力,包括状态空间几何与长期时间特性。

原文摘要 · Abstract (English)

Data-driven inference of the generative dynamics underlying a set of observed time series is of growing interest in machine learning and the natural sciences. In neuroscience, such methods promise to alleviate the need to handcraft models based on biophysical principles and allow to automatize the inference of inter-individual differences in brain dynamics. Recent breakthroughs in training techniques for state space models (SSMs) specifically geared toward dynamical systems (DS) reconstruction (DSR) enable to recover the underlying system including its geometrical (attractor) and long-term statistical invariants from even short time series. These techniques are based on control-theoretic ideas, like modern variants of teacher forcing (TF), to ensure stable loss gradient propagation while training. However, as it currently stands, these techniques are not directly applicable to data modalities where current observations depend on an entire history of previous states due to a signal's filtering properties, as common in neuroscience (and physiology more generally). Prominent examples are the blood oxygenation level dependent (BOLD) signal in functional magnetic resonance imaging (fMRI) or Ca$^{2+}$ imaging data. Such types of signals render the SSM's decoder model non-invertible, a requirement for previous TF-based methods. Here, exploiting the recent success of control techniques for training SSMs, we propose a novel algorithm that solves this problem and scales exceptionally well with model dimensionality and filter length. We demonstrate its efficiency in reconstructing dynamical systems, including their state space geometry and long-term temporal properties, from just short BOLD time series.

动力系统fMRI生成模型神经建模

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