Niogi Sumit N, Mukherjee Pratik, Ghajar Jamshid, Johnson Carl E, Kolster Rachel, Lee Hana, Suh Minah, Zimmerman Robert D, Manley Geoffrey T, McCandliss Bruce D
Sackler Institute for Developmental Psychobiology,Weill Cornell Medical College, New York, NY, USA.
Brain. 2008 Dec;131(Pt 12):3209-21. doi: 10.1093/brain/awn247. Epub 2008 Oct 24.
Memory and attentional control impairments are the two most common forms of dysfunction following mild traumatic brain injury (TBI) and lead to significant morbidity in patients, yet these functions are thought to be supported by different brain networks. This 3 T magnetic resonance diffusion tensor imaging (DTI) study investigates whether microstructural integrity of white matter, as measured by fractional anisotropy (FA) within a small set of individually localized regions of interest (ROIs), is associated with these cognitive domains in normal adults and adults with mild TBI. Results in a sample of 23 normal controls reveal a significant correlation between attentional control and FA within a ROI in the left hemisphere anterior corona radiata. Furthermore, the controls demonstrate a correlation between memory performance and FA in a ROI placed in the uncinate fasciculus. Next, to examine whether these relationships are found in the pathological ranges of attention, memory and microstructural white matter integrity associated with mild TBI, these analyses were applied to a group of 43 mild TBI patients. Results, which generally demonstrated a wider range of attention, memory and FA scores, replicated the correlation between attentional control and FA in left hemisphere anterior corona radiata, as well as the correlation between memory performance and FA in the uncinate fasciculus. These two sets of brain-behaviour relationships were highly specific, as shown by a lack of correlation between attention and uncinate fasciculus FA and the lack of correlation between memory performance and anterior corona radiata FA. Furthermore, a 'correlational double dissociation' was demonstrated to exist between two distinct frontal structures independently associated with attention and memory, respectively, via a series of multiple regression analyses in both normal controls and adults with mild TBI. The results of the multiple regression analyses provide direct evidence that tract-specific variation in microstructural white matter integrity among normal controls and among mild TBI patients can account for much of the variation in performance in specific cognitive domains. More generally, such findings suggest that diffusion anisotropy measurement can be used as a quantitative biomarker for neurocognitive function and dysfunction.
记忆和注意力控制障碍是轻度创伤性脑损伤（TBI）后最常见的两种功能障碍形式，会给患者带来显著的发病率，然而这些功能被认为由不同的脑网络支持。这项3T磁共振扩散张量成像（DTI）研究调查了在一小组个体定位的感兴趣区域（ROI）内通过分数各向异性（FA）测量的白质微观结构完整性是否与正常成年人和轻度TBI成年人的这些认知领域相关。23名正常对照样本的结果显示，左侧半球前放射冠的一个ROI内的注意力控制与FA之间存在显著相关性。此外，对照组显示位于钩束的一个ROI内的记忆表现与FA之间存在相关性。接下来，为了检查在与轻度TBI相关的注意力、记忆和白质微观结构完整性的病理范围内是否能发现这些关系，将这些分析应用于一组43名轻度TBI患者。结果通常显示出更广泛的注意力、记忆和FA分数范围，重复了左侧半球前放射冠内注意力控制与FA之间的相关性，以及钩束内记忆表现与FA之间的相关性。这两组脑 - 行为关系具有高度特异性，表现为注意力与钩束FA之间缺乏相关性，以及记忆表现与前放射冠FA之间缺乏相关性。此外，通过对正常对照和轻度TBI成年人进行一系列多元回归分析，证明在分别与注意力和记忆独立相关的两个不同额叶结构之间存在“相关双分离”。多元回归分析的结果提供了直接证据，即正常对照和轻度TBI患者之间白质微观结构完整性的束特异性变化可以解释特定认知领域表现的大部分变化。更普遍地说，这些发现表明扩散各向异性测量可以用作神经认知功能和功能障碍的定量生物标志物。
