Center for Lifespan Psychology, Max Planck Institute for Human Development, 14195 Berlin, Germany, Beckman Institute for Advanced Science and Technology, University of Illinois, Urbana, Illinois 61820, Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London, London, WC1N 3BG, United Kingdom, Department of Education and Psychology, Freie Universität Berlin, 14195 Berlin, Germany, Department of Psychology, TU Dresden, 01062 Dresden, Germany, Aging Research Center, Karolinska Institute, SE-113 30 Stockholm, Sweden, and Max Planck Institute for Human Cognitive and Brain Sciences, 04103 Leipzig, Germany.
J Neurosci. 2013 Oct 23;33(43):17150-9. doi: 10.1523/JNEUROSCI.1426-13.2013.
The comprehensive relations between healthy adult human brain white matter (WM) microstructure and gray matter (GM) function, and their joint relations to cognitive performance, remain poorly understood. We investigated these associations in 27 younger and 28 older healthy adults by linking diffusion tensor imaging (DTI) with functional magnetic resonance imaging (fMRI) data collected during an n-back working memory task. We present a novel application of multivariate Partial Least Squares (PLS) analysis that permitted the simultaneous modeling of relations between WM integrity values from all major WM tracts and patterns of condition-related BOLD signal across all GM regions. Our results indicate that greater microstructural integrity of the major WM tracts was negatively related to condition-related blood oxygenation level-dependent (BOLD) signal in task-positive GM regions. This negative relationship suggests that better quality of structural connections allows for more efficient use of task-related GM processing resources. Individuals with more intact WM further showed greater BOLD signal increases in typical "task-negative" regions during fixation, and notably exhibited a balanced magnitude of BOLD response across task-positive and -negative states. Structure-function relations also predicted task performance, including accuracy and speed of responding. Finally, structure-function-behavior relations reflected individual differences over and above chronological age. Our findings provide evidence for the role of WM microstructure as a scaffold for the context-relevant utilization of GM regions.
健康成年人大脑白质（WM）微观结构与灰质（GM）功能之间的综合关系，以及它们与认知表现的联合关系，仍然知之甚少。我们通过将弥散张量成像（DTI）与功能磁共振成像（fMRI）数据联系起来，在 27 名年轻成年人和 28 名老年成年人中研究了这些关联，这些数据是在 n-back 工作记忆任务期间收集的。我们提出了一种多元偏最小二乘（PLS）分析的新应用，该方法允许同时对所有主要 WM 束的 WM 完整性值与所有 GM 区域的条件相关 BOLD 信号模式之间的关系进行建模。我们的研究结果表明，主要 WM 束的微观结构完整性越高，与任务相关的 GM 区域中的血氧水平依赖（BOLD）信号之间的关系就越负面。这种负相关关系表明，结构连接的质量越好，允许更有效地利用与任务相关的 GM 处理资源。WM 更完整的个体在注视时进一步表现出典型“任务负性”区域中更大的 BOLD 信号增加，并且显著表现出在任务正性和负性状态之间平衡的 BOLD 反应幅度。结构-功能关系也预测了任务表现，包括响应的准确性和速度。最后，结构-功能-行为关系反映了个体差异，超出了实际年龄。我们的研究结果为 WM 微观结构作为 GM 区域的背景相关利用的支架提供了证据。
