Neuroimaging Of Frontal Lobe Functioning During Cognitio

认知过程中额叶功能的神经影像学

• 批准号: 6823942
• 负责人: Karen FAITH Berman
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF MENTAL HEALTH
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6823942
• 关键词: bioimaging /biomedical imaging; brain circulation; brain imaging /visualization /scanning; clinical research; cognition; frontal lobe /cortex; human subject; memory; neural information processing; neuropsychology; positron emission tomography; verbal behavior

Using functional neuroimaging to determine local neuronal activity, we have found that normal subjects performing tasks involving working memory use a cortical network including dorsolateral prefrontal cortex, inferior parietal lobule, and inferior temporo-occipital cortex. In other tasks related to prefrontal cortex, we have shown, with word generation (verbal fluency) tasks that semantic and phonologic cues activate similar brain regions including anterior cingulate, left frontal cortex, thalamus and cerebellum, but subtle differences exist between them that are consistent with the lesion literature. In a study of cognitive activation in normal aging we found that neurophysiological changes were context dependent. That is, apparent changes over the life span differed in different tasks, depending on the role of the particular neural system for the particular task. In regions where physiological activity is normally suppressed when young subjects perform the tasks older subjects activate more, and, moreover, the more they activate (or fail to suppress), the worse they perform on the tasks. In other areas, where physiological activity is normally increased in young people performing the tasks, older subjects activate less; and the less they activate these regions, the more impaired their performance. We have also confirmed that large-scale changes in brain activity at the systems level (accompanying nonlinear changes in behavior) follow predictions from nonlinear dynamical theory, and we have defined discriminable frontal lobe regions (lateral prefrontal cortex and anterior cingulate cortex) that subserve different cognitive components in switching between tasks (overcoming the residual inhibition of previous task demands and initiating a new task, respectively). We have also shown that the neural system patterns activated in individual healthy subjects reflect their levels of performance and cognitive strategies (verbal versus spatial) on a working memory task.

使用功能性神经成像来确定局部神经元活动，我们发现正常受试者执行涉及工作记忆的任务使用包括背外侧前额叶皮层、顶下小叶和下颞枕叶皮层的皮层网络。在与前额叶皮层相关的其他任务中，我们已经证明，在单词生成（言语流畅性）任务中，语义和语音线索激活了相似的大脑区域，包括前扣带回，左额叶皮层，丘脑和小脑，但它们之间存在细微的差异，这与损伤文献一致。在一项关于正常衰老过程中认知激活的研究中，我们发现神经生理学变化是依赖于环境的。也就是说，在不同的任务中，寿命的明显变化是不同的，这取决于特定神经系统在特定任务中的作用。在年轻人执行任务时生理活动通常受到抑制的区域，老年人激活更多，而且，他们激活（或无法抑制）越多，他们在任务中的表现就越差。在其他区域，年轻人在执行任务时生理活动通常会增加，老年受试者激活较少;他们激活这些区域的次数越少，他们的表现就越受损。我们还证实，在系统水平上，大脑活动的大规模变化（伴随行为的非线性变化）遵循非线性动力学理论的预测，并且我们定义了可辨别的额叶区域（外侧前额叶皮层和前扣带皮层），其在任务之间的切换（分别克服先前任务需求的残余抑制和启动新任务）中帮助不同的认知组件。我们还表明，在个体健康受试者中激活的神经系统模式反映了他们在工作记忆任务中的表现和认知策略（语言与空间）水平。