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）：本提案的目的是应用经颅磁刺激（TMS）和功能性磁共振成像（fMRI）来完善老年人健康额叶功能的模型。额叶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，老年人在年轻人表现出单侧激活的情况下表现出双侧额叶激活。双侧激活能力更强的老年人表现出更好的记忆力。尚未确定这些额外区域是否参与执行的任务。 TMS 将用于破坏老年人更强烈地招募的焦点区域，以确定这些区域是否是记忆处理所必需的。第一项研究应用了言语工作记忆范式，该范式在功能磁共振成像中显示，年轻人主要是左额叶激活，而老年人主要是双侧额叶激活。之前的一项 TMS 研究表明，在年轻人中，短暂的右额叶受累先于左额叶受累。如果老年人表现出不同的右半球募集时间模式，这可能会导致功能磁共振成像激活差异。第二项和第三项研究将年轻人的情景记忆 TMS 研究扩展到老年人。功能成像研究表明，左额叶在编码过程中比检索过程中更活跃，而右额叶在检索过程中比编码过程中更活跃。之前的 TMS 研究表明，在年轻人中，年轻人左额叶与右额叶的 TMS 破坏程度遵循基于功能激活相对差异的预测。由于老年人总体上表现出较少的偏侧功能激活，因此我们假设 TMS 刺激会同等地破坏两个半球的表现。额叶 fMRI 激活不对称程度的个体差异将与左右 TMS 的性能中断程度相关。