FMRI and TMS Analysis of Frontal Lobes in Aging

额叶衰老过程中的 FMRI 和 TMS 分析

• 批准号: 6973928
• 负责人: ALLYSON C ROSEN
• 金额: $ 12.73万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-09-30 至 2010-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6973928
• 关键词: age difference; behavior test; behavioral /social science research tag; brain imaging /visualization /scanning; brain interhemispheric activity; brain morphology; cerebral dominance; clinical research; cognition disorders; data collection methodology /evaluation; executive function; frontal lobe /cortex; functional magnetic resonance imaging; human old age (65+); human subject; neural information processing; neuropsychological tests; short term memory; transcranial magnetic stimulation

DESCRIPTION (provided by applicant): The aim of this proposal is to apply transcranial magnetic stimulation (TMS) and functional MRI (fMRI) to refine models of healthy frontal lobe functioning in older adults. Frontal lobe functioning changes with increasing age. FMRI activation studies of young and older adults performing memory tasks demonstrate that older adults exhibit bilateral frontal lobe activation under conditions where young adults display unilateral activation. Older adults demonstrating bilateral activation more strongly demonstrate better memory. It has not been established whether these additional regions are involved in the task performed. TMS will be applied to disrupt focally regions more intensely recruited by older adults to determine whether those areas are necessary for memory processing. The first study applies a verbal working memory paradigm which in fMRI has demonstrated predominantly left frontal activation in young adults and bilateral activation in older adults. A previous TMS study suggested that transient right frontal involvement precedes left frontal involvement in young adults. If older adults demonstrate a different temporal pattern of right hemisphere recruitment, this could contribute to fMRI activation differences. The second and third studies extend to older adults a TMS study of episodic memory performed in young adults. Functional imaging research suggests that the left frontal lobe is more active during encoding than retrieval and the right frontal lobe is more active during retrieval than encoding. The previous TMS study demonstrated that in young adults, degree of disruption with TMS in the left versus right frontal lobes of young adults followed the predictions based on relative differences in functional activation. Because older adults demonstrate less lateralized functional activation in general, we hypothesize that TMS stimulation will disrupt performance equally in both hemispheres. Individual differences in the degree of asymmetry in frontal lobe fMRI activation will be associated with degree of performance disruption with right versus left TMS.

描述（由申请人提供）：该建议的目的是应用经颅磁刺激（TMS）和功能性MRI（fMRI）来完善老年人健康额叶功能的模型。额叶的功能随着年龄的增长而变化。对执行记忆任务的年轻人和老年人的FMRI激活研究表明，在年轻人显示单侧激活的情况下，老年人表现出双侧额叶激活。表现出双边激活的老年人更强烈地表现出更好的记忆。尚未确定执行的任务是否涉及这些其他区域。 TMS将应用于更严格地招募老年人的重点区域，以确定这些领域是否需要用于记忆处理。第一项研究采用了口头工作记忆范式，在fMRI中，年轻人的额叶激活主要是左额激活，而在老年人中则是双边激活。先前的TMS研究表明，短暂的右额叶参与之前是年轻人的左额叶参与。如果老年人表现出右半球募集的不同时间模式，则可能导致fMRI激活差异。第二和第三研究扩展到老年人一项对年轻人进行的情节记忆的TMS研究。功能成像研究表明，左额叶在编码过程中比检索更活跃，并且右额叶在检索过程中比编码更活跃。先前的TMS研究表明，在年轻人中，年轻人的左侧与右额叶的破坏程度遵循了基于功能激活的相对差异的预测。由于老年人通常表现出较少的侧向功能激活，因此我们假设在两个半球中，TMS刺激会平均破坏性能。额叶fMRI激活中不对称程度的个体差异将与右TMS相比的性能中断程度有关。