BOLD and its discontents: age-differences in the neurophysiology of fMRI signal

BOLD 及其不满：fMRI 信号神经生理学的年龄差异

• 批准号: 9134043
• 负责人: Hanzhang Lu
• 金额: $ 32.81万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-01 至 2020-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9134043
• 关键词: Adult; Age; Aging; Base of the Brain; Bilateral; Blood; Blood Vessels; Blood flow; Brain; Brain region; Cerebrovascular Circulation; Cerebrum; Cognitive; Core-Binding Factor; Coupling; Dependence; Event-Related Potentials; Fingers; Frequencies; Functional Magnetic Resonance Imaging; Grant; Health; Imaging Techniques; Imaging technology; Individual; Knowledge; Literature; Longevity; Magnetic Resonance Imaging; Measures; Mediating; Mediator of activation protein; Memory; Metabolic; Metabolism; Methods; Modeling; Motor; Motor Cortex; Nature; Neurocognitive; Neurons; Neurophysiology - biologic function; Oxygen; Pattern; Perception; Performance; Physiologic pulse; Physiological; Physiology; Prefrontal Cortex; Psyche structure; Psychometrics; Role; Sensory; Short-Term Memory; Signal Transduction; Synapses; Testing; Thumb structure; Time; Variant; Visual Cortex; age difference; age group; age related; aging brain; base; blood oxygen level dependent; brain metabolism; cognitive function; cognitive task; indexing; insight; memory process; neurophysiology; neurovascular; processing speed; relating to nervous system; response; theories; vascular contributions; visual motor; young adult

 DESCRIPTION (provided by applicant): Neurocognitive aging theories are based on age differences in blood-oxygen-level-dependent signal (BOLD) as measured with functional magnetic resonance imaging (fMRI). However, there is a growing recognition that BOLD age-changes result from many physiologic, neural, and cognitive factors that remain poorly understood and complicate interpretation of BOLD as a straightforward index of age-related neural change. More precise neurocognitive aging hypotheses can be formulated once the physiologic factors underlying age-related BOLD change are disentangled and measured separately. Three such factors are changes in cerebral blood flow (¿CBF), that deliver O2 to active neurons, change of the cerebral oxygen metabolism rate (¿CMRO2), an estimate of metabolic neural activity, and event-related potential (ERP), an estimate of post-synaptic neural activity. These factors have not been studied as extensively in aging as we propose to here. Using a dual-echo BOLD/ASL MRI pulse sequence, we have recently demonstrated that these important physiologic factors can be measured in brain aging studies, simultaneously with conventional BOLD signal. In this proposal, we plan to conduct a more systematic study to assess the relationship between age and task-evoked physiologic responses in blood flow, blood oxygenation, brain metabolism, as well as the influence of task-demand on these factors. We propose a general model on age-related changes in brain physiology that can reconcile diverse results in neurocognitive aging literature. We test the model in three Aims. Aims 1 and 2 are to measure age differences in visual and motor cortex BOLD, ERP, CMRO2, and CBF response to sensory and motor task-demands of varying strength. In Aim 3 we will assess the role of CBF-CMRO2 uncoupling in age- related working memory and processing speed changes. Achieving our grant aims will yield new knowledge about (1) basic mechanisms of age-changes in neural function, (2) age-related neural-vascular changes that give rise to BOLD changes, and (3) how these basic mechanisms are tied to performance.