Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA 02129, USA.
Cereb Cortex. 2012 May;22(5):1038-51. doi: 10.1093/cercor/bhr172. Epub 2011 Jul 17.
Advanced aging is associated with reduced attentional control and less flexible information processing. Here, the origins of these cognitive effects were explored using a functional magnetic resonance imaging task that systematically varied demands to shift attention and inhibit irrelevant information across task blocks. Prefrontal and parietal regions previously implicated in attentional control were recruited by the task and most so for the most demanding task configurations. A subset of older individuals did not modulate activity in frontal and parietal regions in response to changing task requirements. Older adults who did not dynamically modulate activity underperformed their peers and scored more poorly on neuropsychological measures of executive function and speed of processing. Examining 2 markers of preclinical pathology in older adults revealed that white matter hyperintensities (WMHs), but not high amyloid burden, were associated with failure to modulate activity in response to changing task demands. In contrast, high amyloid burden was associated with alterations in default network activity. These results suggest failure to modulate frontal and parietal activity reflects a disruptive process in advanced aging associated with specific neuropathologic processes.
衰老会导致注意力控制能力下降和信息处理的灵活性降低。在这里，我们使用功能磁共振成像任务来探索这些认知效应的起源，该任务系统地改变了注意力转移和抑制任务块中不相关信息的要求。先前与注意力控制有关的前额叶和顶叶区域被任务招募，在最具挑战性的任务配置中最为明显。一部分老年人在响应不断变化的任务要求时不会调节额叶和顶叶区域的活动。不能根据任务要求动态调节活动的老年人表现不如同龄人，在执行功能和处理速度的神经心理学测量中得分也较低。在老年人中检查了 2 个临床前病理学标志物，结果表明，白质高信号（WMHs），而不是高淀粉样蛋白负荷，与不能根据任务需求调节活动有关。相比之下，高淀粉样蛋白负荷与默认网络活动的改变有关。这些结果表明，无法调节额叶和顶叶活动反映了与特定神经病理学过程相关的衰老相关的破坏性过程。
