用新方法融合脑结构与功能影像,更好捕捉神经网络关联。
Copula-Linked Parallel ICA: A Method for Coupling Structural and Functional MRI brain Networks
- 结合深度学习、核密度估计和独立成分分析,建模多模态脑网络耦合关系
- 在阿尔茨海默病数据中识别出多个关键脑网络的动态连接模式
- 适合研究脑疾病机制或跨模态脑成像的科研人员
不同脑成像模态为大脑功能与结构提供独特视角。结合它们可深化对神经机制的理解。以往融合功能磁共振(fMRI)与结构磁共振(sMRI)的研究表明该方法有效。由于sMRI无时间信息,现有融合方法常将fMRI的时间动态压缩为统计量,损失丰富时序特征。基于结构与功能网络在静息态下存在共变现象的观察,我们提出一种新方法——共现并行独立成分分析(CLiP-ICA),融合深度学习、核密度估计与独立成分分析。该方法分别估计各模态的独立源,并通过基于核密度估计的模型关联fMRI与sMRI的空间源,实现更灵活的时空数据整合。我们在阿尔茨海默病神经影像计划(ADNI)数据上验证了该方法。结果表明,CLiP-ICA能有效捕捉强弱关联的脑网络,包括小脑、感觉运动、视觉、认知控制与默认模式网络。其识别出更多有意义的成分且减少伪影,解决了独立成分分析中模型阶数选择的长期难题。此外,它揭示了认知衰退不同阶段的功能连接复杂变化:认知正常者在感觉运动与视觉网络中表现出更高连接性,而患者则呈现可能的代偿机制模式。
原文摘要 · Abstract (English)
Different brain imaging modalities offer unique insights into brain function and structure. Combining them enhances our understanding of neural mechanisms. Prior multimodal studies fusing functional MRI (fMRI) and structural MRI (sMRI) have shown the benefits of this approach. Since sMRI lacks temporal data, existing fusion methods often compress fMRI temporal information into summary measures, sacrificing rich temporal dynamics. Motivated by the observation that covarying networks are identified in both sMRI and resting-state fMRI, we developed a novel fusion method, by combining deep learning frameworks, copulas and independent component analysis (ICA), named copula linked parallel ICA (CLiP-ICA). This method estimates independent sources for each modality and links the spatial sources of fMRI and sMRI using a copula-based model for more flexible integration of temporal and spatial data. We tested CLiP-ICA using data from the Alzheimer's Disease Neuroimaging Initiative (ADNI). Our results showed that CLiP-ICA effectively captures both strongly and weakly linked sMRI and fMRI networks, including the cerebellum, sensorimotor, visual, cognitive control, and default mode networks. It revealed more meaningful components and fewer artifacts, addressing the long-standing issue of optimal model order in ICA. CLiP-ICA also detected complex functional connectivity patterns across stages of cognitive decline, with cognitively normal subjects generally showing higher connectivity in sensorimotor and visual networks compared to patients with Alzheimer, along with patterns suggesting potential compensatory mechanisms.
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