Lamar Melissa, Yousem David M, Resnick Susan M
Laboratory of Personality and Cognition, Gerontology Research Center, National Institute on Aging, Baltimore, MD 21224, USA.
Neuroimage. 2004 Apr;21(4):1368-76. doi: 10.1016/j.neuroimage.2003.11.018.
Several investigations have suggested that the orbitofrontal cortex (OFC) may be particularly vulnerable to the effects of age-related changes. We recently reported behavioral data indicating greater age differences in orbitofrontal tasks when directly compared to tasks tapping dorsolateral prefrontal functions. The present study was designed to investigate the neural underpinnings of age differences in OFC functioning. Event-related functional magnetic resonance imaging (fMRI) was performed during delayed match and nonmatch to sample tasks, previously shown to differentially activate medial and lateral OFC in young adults. Sixteen healthy younger [age = 26.7(5.6)] and 16 healthy older individuals [age = 69.1 + 5.6] with similar levels of education and general cognitive functioning participated in the experiment. Participants chose the stimulus from a pair of stimuli matching a previously viewed target (match to sample) or chose the nontarget item (nonmatch to sample) depending upon a trial-specific instruction word. Consistent with previous studies, SPM99 analyses of the younger age group revealed activation for medial OFC regions during the match task compared to the nonmatch task and lateral OFC activation during the nonmatch task compared to the match task. In contrast, older adults showed prefrontal activation only during the match relative to the nonmatch task and posterior temporal and limbic involvement during the nonmatch relative to the match task. Between-group analyses confirmed within-group results suggesting differential age-related recruitment of prefrontal regions when performing match and nonmatch tasks. Results suggest that OFC recruitment during these cognitive tasks changes with age and should be evaluated within the context of other prefrontal subregions to further define differential age effects on frontal functions.
多项研究表明，眶额皮质（OFC）可能特别容易受到与年龄相关变化的影响。我们最近报告的行为数据表明，与测试背外侧前额叶功能的任务相比，眶额任务中的年龄差异更大。本研究旨在调查眶额皮质功能中年龄差异的神经基础。在延迟匹配和非匹配样本任务期间进行了事件相关功能磁共振成像（fMRI），此前的研究表明，这些任务在年轻人中会分别激活内侧和外侧眶额皮质。16名健康的年轻人[年龄=26.7（5.6）]和16名健康的老年人[年龄=69.1 + 5.6]参与了实验，他们的教育水平和一般认知功能相似。参与者根据特定试验的指令词，从一对与先前查看的目标匹配的刺激中选择刺激（匹配样本），或选择非目标项目（非匹配样本）。与先前的研究一致，对年轻年龄组的SPM99分析显示，与非匹配任务相比，匹配任务期间内侧眶额皮质区域激活，与匹配任务相比，非匹配任务期间外侧眶额皮质激活。相比之下，老年人仅在匹配任务相对于非匹配任务期间表现出前额叶激活，在非匹配任务相对于匹配任务期间表现出颞叶后部和边缘系统的参与。组间分析证实了组内结果，表明在执行匹配和非匹配任务时，前额叶区域的年龄相关募集存在差异。结果表明，在这些认知任务中，眶额皮质的募集随年龄而变化，应在其他前额叶亚区域的背景下进行评估，以进一步确定年龄对额叶功能的不同影响。
