Biomedical Health Sciences Institute, Division of Neuroscience, University of Georgia, Psychology Building, Athens, GA 30602, United States.
Neuropsychologia. 2013 Sep;51(11):2281-93. doi: 10.1016/j.neuropsychologia.2013.07.023. Epub 2013 Aug 6.
Memory dysfunction in mild cognitive impairment (MCI) due to Alzheimer's pathology is primarily associated with episodic memory deficits linked to deterioration of the medial temporal lobes (MTLs). Currently, there is a call to discover novel biomarkers of MCI in order to improve research criteria. Functional activation differences in MCI during episodic memory-task performance are often evidenced in the MTLs, and frontal and parietal lobes, but it has been suggested that examination of working memory (WM) differences may be more useful in detecting MCI. In the current study, MCI and control participants performed a complex WM span (CWMS) task while functional magnetic resonance imaging (fMRI) data were acquired. Results indicated hyper-activation of the lateral temporal lobes, MTLs, and frontal and parietal regions during encoding and maintenance, and hyper-activation of the lateral temporal, frontal, and parietal lobes during CWMS recall for the MCI participants. Medial and lateral temporal differences during encoding and maintenance are consistent with previous findings, but lateral temporal differences are often not elaborated upon. Hyper-activation of the lateral temporal lobes during WM encoding and maintenance, and also during recall, suggests that this region may provide valuable information regarding WM impairment in MCI and Alzheimer's. Given that whole-brain functional imaging of the MTLs is often limited due to artifact and partial voluming of sub-fields, examination of lateral temporal differences may provide a novel biomarker related to WM impairment in MCI.
阿尔茨海默病病理学导致的轻度认知障碍 (MCI) 的记忆功能障碍主要与内侧颞叶 (MTLs) 恶化相关的情景记忆缺陷有关。目前，人们呼吁发现 MCI 的新生物标志物，以改善研究标准。在进行情景记忆任务时，MCI 患者的 MTLs、额叶和顶叶中经常出现功能激活差异，但有人认为检查工作记忆 (WM) 差异可能更有助于检测 MCI。在当前的研究中，MCI 和对照组参与者在执行复杂的 WM 跨度 (CWMS) 任务时，同时获取功能磁共振成像 (fMRI) 数据。结果表明，在编码和维持期间，外侧颞叶、MTLs 和额叶和顶叶区域过度活跃，在 CWMS 回忆期间，MCI 参与者的外侧颞叶、额叶和顶叶过度活跃。编码和维持期间内侧和外侧颞叶的差异与之前的研究结果一致，但外侧颞叶的差异通常没有详细说明。WM 编码和维持期间以及回忆期间外侧颞叶的过度活跃表明，该区域可能为 MCI 和阿尔茨海默病的 WM 损伤提供有价值的信息。鉴于 MTLs 的全脑功能成像由于伪影和子区域的部分体积而常常受到限制，因此检查外侧颞叶的差异可能提供与 MCI 中 WM 损伤相关的新型生物标志物。
