Nomi Jason S, Bzdok Danilo, Li Jingwei, Bolt Taylor, Chang Catie, Kornfeld Salome, Goodman Zachary T, Yeo B T Thomas, Spreng R Nathan, Uddin Lucina Q
Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, CA, United States.
Department of Biomedical Engineering, Montreal Neurological Institute (MNI), Brain-imaging institute (BIC), McGill University, Montreal, QC, Canada; Mila - Quebec Artificial Intelligence Institute, Quebec, Canada.
Imaging Neurosci (Camb). 2024 Mar 8;2. doi: 10.1162/imag_a_00101. eCollection 2024.
The global signal (GS) in resting-state functional MRI (fMRI), known to contain artifacts and non-neuronal physiological signals, also contains important neural information related to individual state and trait characteristics. Here, we show distinct linear and curvilinear relationships between GS topography and age in a cross-sectional sample of individuals (6-85 years old) representing a significant portion of the lifespan. Subcortical brain regions such as the thalamus and putamen show linear associations with the GS across age. The thalamus has stronger contributions to the GS in older-age individuals compared with younger-aged individuals, while the putamen has stronger contributions in younger individuals compared with older individuals. The subcortical nucleus basalis of Meynert shows a u-shaped pattern similar to cortical regions within the lateral frontoparietal network and dorsal attention network, where contributions of the GS are stronger at early and old age, and weaker in middle age. This differentiation between subcortical and cortical brain activity across age supports a dual-layer model of GS composition, where subcortical aspects of the GS are differentiated from cortical aspects of the GS. We find that these subcortical-cortical contributions to the GS depend strongly on age across the lifespan of human development. Our findings demonstrate how neurobiological information within the GS differs across development and highlight the need to carefully consider whether or not to remove this signal when investigating age-related functional differences in the brain.
静息态功能磁共振成像（fMRI）中的全局信号（GS），已知包含伪影和非神经元生理信号，同时也包含与个体状态和特质特征相关的重要神经信息。在此，我们在一个涵盖了生命周期中很大一部分的个体横断面样本（6至85岁）中，展示了GS地形图与年龄之间不同的线性和曲线关系。诸如丘脑和壳核等皮质下脑区在不同年龄段与GS呈现线性关联。与年轻个体相比，丘脑在老年个体中对GS的贡献更强，而壳核在年轻个体中比老年个体对GS的贡献更强。迈内特基底核呈现出与外侧额顶叶网络和背侧注意网络内的皮质区域相似的u形模式，其中GS的贡献在早年和老年时更强，而在中年时较弱。这种皮质下和皮质脑活动在不同年龄段的差异支持了GS组成的双层模型，其中GS的皮质下方面与GS的皮质方面有所不同。我们发现，这些对GS的皮质下 - 皮质贡献在人类发育的整个生命周期中强烈依赖于年龄。我们的研究结果表明了GS内的神经生物学信息在不同发育阶段是如何不同的，并强调了在研究大脑中与年龄相关的功能差异时，需要仔细考虑是否去除该信号。
