Yan Hao, Feng Yanqin, Wang Qian
Neuroimaging Laboratory, School of Biomedical Engineering, Shenzhen University Health Science Center, Shenzhen 518060, China; Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China; Departments of Linguistics and Psychology, Xidian University, Xi'an 710071, China.
Departments of Linguistics and Psychology, Xidian University, Xi'an 710071, China.
Neural Plast. 2016;2016:6353845. doi: 10.1155/2016/6353845. Epub 2016 Dec 15.
Traumatic brain injuries (TBIs) are generally recognized to affect episodic memory. However, less is known regarding how external force altered the way functionally connected brain structures of the episodic memory system interact. To address this issue, we adopted an effective connectivity based analysis, namely, multivariate Granger causality approach, to explore causal interactions within the brain network of interest. Results presented that TBI induced increased bilateral and decreased ipsilateral effective connectivity in the episodic memory network in comparison with that of normal controls. Moreover, the left anterior superior temporal gyrus (aSTG, the concept forming hub), left hippocampus (the personal experience binding hub), and left parahippocampal gyrus (the contextual association hub) were no longer network hubs in TBI survivors, who compensated for hippocampal deficits by relying more on the right hippocampus (underlying perceptual memory) and the right medial frontal gyrus (MeFG) in the anterior prefrontal cortex (PFC). We postulated that the overrecruitment of the right anterior PFC caused dysfunction of the strategic component of episodic memory, which caused deteriorating episodic memory in mTBI survivors. Our findings also suggested that the pattern of brain network changes in TBI survivors presented similar functional consequences to normal aging.
创伤性脑损伤（TBI）通常被认为会影响情景记忆。然而，关于外力如何改变情景记忆系统中功能连接的脑结构之间的相互作用方式，我们了解得较少。为了解决这个问题，我们采用了一种基于有效连接性的分析方法，即多变量格兰杰因果关系方法，来探索感兴趣的脑网络内的因果相互作用。结果表明，与正常对照组相比，TBI导致情景记忆网络中双侧有效连接性增加，同侧有效连接性降低。此外，在TBI幸存者中，左侧颞上回前部（aSTG，概念形成枢纽）、左侧海马体（个人经历绑定枢纽）和左侧海马旁回（情境关联枢纽）不再是网络枢纽，他们通过更多地依赖右侧海马体（潜在的感知记忆）和前额叶皮质（PFC）前部的右侧内侧额叶回（MeFG）来弥补海马体缺陷。我们推测，右侧前额叶皮质过度激活导致情景记忆的策略成分功能障碍，这导致了mTBI幸存者情景记忆的恶化。我们的研究结果还表明，TBI幸存者脑网络变化的模式与正常衰老呈现出相似的功能后果。
