Hao Jing, Li Kuncheng, Li Ke, Zhang Dexuan, Wang Wei, Yang Yanhui, Yan Bin, Shan Baoci, Zhou Xiaolin
Department of Radiology, Xuanwu Hospital, Capital University of Medical Sciences, No. 45 Changchun Street, Beijing 100053, PR China.
Neurosci Lett. 2005 Sep 2;385(1):18-23. doi: 10.1016/j.neulet.2005.05.028.
Cognitive and neuroscience studies indicate that attentional operations are impaired in Alzheimer's disease (AD). Our goal was to define the anatomical areas of activation associated with visual attention processing and to define deficits or changes that may occur in AD patients compared with control group. Thirteen AD patients and 13 age- and education-matched normal controls were tested in two visual search tasks (one was a conjunction task, where feature binding is required. The other was a subset task, where group stimuli is needed without feature binding) using fMRI techniques. After stereotactical normalization, voxel-by-voxel t statistics was used to compare activated brain areas between patients and control subjects. Our findings suggest that both search tasks are controlled by partially overlapping cerebral networks, including parietal, frontal and occipital-temporal cortical regions and primary visual cortex. The AD patient group showed less activation in both parietal lobes and the left frontal regions, while increased activation was found in the right frontal lobes and the right occipito-temporal cortical regions with the conjunction task. In the subset task, decreased activation in AD patients was seen in the left parietal lobe and bilateral frontal lobes, while increased activation was seen in both medial temporal lobes. In addition, for the comparison between tasks, The difference is very small for AD patients. Control group showed a higher amplitude in the right prefrontal region, temporal cortical regions and parietal lobe. These results indicate that attention deficits in AD patients may be attributed to both binding problem and grouping inefficiency.
认知和神经科学研究表明，阿尔茨海默病（AD）患者的注意力操作存在受损情况。我们的目标是确定与视觉注意力处理相关的激活解剖区域，并确定与对照组相比AD患者可能出现的缺陷或变化。使用功能磁共振成像（fMRI）技术，对13名AD患者和13名年龄及教育程度相匹配的正常对照者进行了两项视觉搜索任务测试（一项是需要特征捆绑的联合任务，另一项是无需特征捆绑对刺激进行分组的子集任务）。在进行立体定向标准化后，采用逐体素t统计量来比较患者和对照者之间的脑激活区域。我们的研究结果表明，两项搜索任务均由部分重叠的脑网络控制，包括顶叶、额叶和枕颞皮质区域以及初级视觉皮层。AD患者组在双侧顶叶和左侧额叶区域的激活较少，而在联合任务中右侧额叶和右侧枕颞皮质区域的激活增加。在子集任务中，AD患者左侧顶叶和双侧额叶的激活减少，而双侧内侧颞叶的激活增加。此外，对于任务之间的比较，AD患者的差异非常小。对照组在右侧前额叶区域、颞皮质区域和顶叶的激活幅度更高。这些结果表明，AD患者的注意力缺陷可能归因于捆绑问题和分组效率低下。
