Oh Hwamee, Steffener Jason, Razlighi Qolamreza R, Habeck Christian, Liu Dan, Gazes Yunglin, Janicki Sarah, Stern Yaakov
Cognitive Neuroscience Division, Department of Neurology, Columbia University College of Physicians and Surgeons, New York, NY, USA.
Cognitive Neuroscience Division, Department of Neurology, Columbia University College of Physicians and Surgeons, New York, NY, USA.
Neurobiol Aging. 2015 Dec;36(12):3247-3254. doi: 10.1016/j.neurobiolaging.2015.08.016. Epub 2015 Aug 24.
The accumulation of amyloid-beta (Aβ) peptides, a pathologic hallmark of Alzheimer's disease, has been associated with functional alterations in cognitively normal elderly, most often in the context of episodic memory with a particular emphasis on the medial temporal lobes. The topography of Aβ deposition, however, highly overlaps with frontoparietal control (FPC) regions implicated in cognitive control/working memory. To examine Aβ-related functional alternations in the FPC regions during a working memory task, we imaged 42 young and 57 cognitively normal elderly using functional magnetic resonance imaging during a letter Sternberg task with varying load. Based on (18)F-florbetaben-positron emission tomography scan, we determined older subjects' amyloid positivity (Aβ+) status. Within brain regions commonly recruited by all subject groups during the delay period, age and Aβ deposition were independently associated with load-dependent frontoparietal hyperactivation, whereas additional compensatory Aβ-related hyperactivity was found beyond the FPC regions. The present results suggest that Aβ-related hyperactivation is not specific to the episodic memory system but occurs in the PFC regions as well.
淀粉样β蛋白(Aβ)肽的积累是阿尔茨海默病的一个病理标志,它与认知正常的老年人的功能改变有关,最常见于情景记忆的背景下,尤其着重于内侧颞叶。然而,Aβ沉积的拓扑结构与涉及认知控制/工作记忆的额顶叶控制(FPC)区域高度重叠。为了在工作记忆任务期间检查FPC区域中与Aβ相关的功能改变,我们在执行不同负荷的字母斯特恩伯格任务期间,使用功能磁共振成像对42名年轻人和57名认知正常的老年人进行了成像。基于(18)F-氟代苯并噻唑正电子发射断层扫描,我们确定了老年受试者的淀粉样蛋白阳性(Aβ+)状态。在所有受试者组在延迟期共同激活的脑区中,年龄和Aβ沉积与负荷依赖性额顶叶过度激活独立相关,而在FPC区域之外还发现了额外的与Aβ相关的代偿性过度激活。目前的结果表明,与Aβ相关的过度激活并非情景记忆系统所特有,在额叶前额叶皮质区域也会出现。