Johnson Sterling C, Schmitz Taylor W, Asthana Sanjay, Gluck Mark A, Myers Catherine
Geriatric Research Education and Clinical Center, Wm. S. Middleton VA Hospital, Madison, WI 53705, USA.
Neuropsychol Dev Cogn B Aging Neuropsychol Cogn. 2008 Mar;15(2):129-45. doi: 10.1080/13825580601139444.
The ability to form associations between choice alternatives and their contingent outcomes is an important aspect of learning that may be sensitive to hippocampal dysfunction in memory disorders of aging such as amnestic mild cognitive impairment (MCIa), or early Alzheimer disease. In this preliminary study we examined brain activation using functional magnetic resonance imaging (fMRI) in 12 healthy elderly participants and nine patients with MCIa during an associative learning task. Using a high-field 3.0-Tesla MRI scanner, we examined the dynamic neural response during associative learning over trials. The slope of signal attenuation associated with learning was analyzed for differences between groups within an a priori defined hippocampal region. Results indicated dynamic signal attenuation associated with learning in the healthy elderly sample, but not in MCIa. The absence of an associative learning effect in the MCIa sample reaffirms an important link between the learning difficulties that are commonly encountered in MCIa and the mesial temporal region.
在诸如遗忘型轻度认知障碍(MCIa)或早期阿尔茨海默病等衰老记忆障碍中,选择项与其相应结果之间形成关联的能力是学习的一个重要方面,可能对海马体功能障碍敏感。在这项初步研究中,我们使用功能磁共振成像(fMRI)对12名健康老年参与者和9名MCIa患者在联想学习任务期间的大脑激活情况进行了检查。使用高场3.0特斯拉MRI扫描仪,我们在多次试验中检查了联想学习期间的动态神经反应。在一个预先定义的海马体区域内,分析了与学习相关的信号衰减斜率,以比较两组之间的差异。结果表明,在健康老年样本中存在与学习相关的动态信号衰减,而在MCIa样本中则不存在。MCIa样本中缺乏联想学习效应,再次证实了MCIa中常见的学习困难与内侧颞叶区域之间的重要联系。