Towards an Improved Understanding of BOLD Signal Changes

加深对 BOLD 信号变化的理解

• 批准号: 7615632
• 负责人: R Todd Constable
• 金额: $ 36.16万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-07-20 至 2011-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7615632
• 关键词: Accounting; Action Potentials; Area; Back; Blood Vessels; Brain; Cerebrovascular Circulation; Cerebrum; Choices and Control; Cognition; Cognitive; Coupling; Data; Detection; Electrodes; Electroencephalography; Epilepsy; Frequencies; Functional Imaging; Functional Magnetic Resonance Imaging; Implanted Electrodes; Lead; Lesion; Link; Measures; Medial; Memory; Metabolic; Metabolism; Methods; Modeling; Nature; Neurons; Operative Surgical Procedures; Output; Oxygen; Oxygen Consumption; Patients; Physiological; Prefrontal Cortex; Process; Proxy; Relative (related person); Research Personnel; Short-Term Memory; Signal Transduction; Source; Steel; Stimulus; Surface; Synapses; Synaptic Potentials; Temporal Lobe; Testing; Time; Variant; Work; base; blood oxygen level dependent; cingulate cortex; cognitive function; extracellular; improved; information processing; insight; neocortical; neurophysiology; novel; programs; relating to nervous system; relational memory; research study; response

DESCRIPTION (provided by applicant): Sharp transients, in electrical recordings, represent a measure of neural activity corresponding to an action potential at a single neuron. Such spike activity reflects the output of a given brain area, yet many regions receive input in the form of excitatory or inhibitory synaptic potentials without generating spikes. This input activity is an important form of computational integration, detected in extracellular recordings as perturbations of the local field potential (LFP). Quantitative analysis of the LFP is performed in the frequency domain, providing a measure of synchronous activity across neurons. Logothetis et al. (2001) showed that BOLD may reflect an area's input in the form of synaptic potentials, rather than its output in the form of spikes. Synaptic inputs can be excitatory or inhibitory, and both forms involve metabolic demands that may alter BOLD and complicate models interpreting BOLD as a proxy for cognitive engagement. The time- courses of oscillations in various frequency bands, and excitatory and inhibitory synaptic potentials, and the relationship between these forms of activity and cognition as reflected by BOLD, is poorly understood. Thus, it is essential to examine the correspondence between certain forms of neural activity, BOLD, and the engagement of cognitive processes. Negative BOLD signals in some cases, for example, demand a nuanced interpretation. The subtractive nature of fMRI initially suggests that negative BOLD simply reflects increased activation during the baseline. However, a number of findings have suggested that negative BOLD represents a distinct phenomenon. This proposal is focused on examining the evidence that negative BOLD reflects decreases in neural activity, associated with cognition. Calibrated MR measures of BOLD and CBF will be performed using tasks previously shown to produce reliable deactivations. These MR measures of flow and oxygenation will be used to determine relative CMRO2 and the oxygen extraction to fully assess the physiologic underpinnings of BOLD. Simultaneous EEC will be recorded and EEC power in multiple frequency bands compared with the MR measures. Much work has been performed characterizing EEC changes in the tasks to be used, but little work has attempted to relate EEC to MR signals. This work will provide insight into the relationship between MR signal changes in cognitive tasks, and EEC changes as measured with surface, and in a limited number of patients, subdural electrodes.

描述（由申请人提供）：在电记录中，尖锐的瞬变代表了与单个神经元处动作电位相对应的神经活动的度量。这种尖峰活性反映了给定大脑区域的输出，但是许多区域以兴奋性或抑制性突触电位的形式接收了输入，而不会产生尖峰。该输入活动是计算整合的一种重要形式，在细胞外记录中检测到局部场电位（LFP）的扰动。 LFP的定量分析是在频域中进行的，提供了整个神经元同步活性的度量。 Logothetis等。 （2001年）表明，粗体可能以突触电位的形式反映了一个区域的输入，而不是以尖峰形式的输出来反映其输出。突触输入可以是兴奋性的或抑制性的，两种形式都涉及代谢需求，这些需求可能会改变大胆而复杂的模型，将大胆解释为认知参与的代理。众所周知，各种频带中的振荡和兴奋性和抑制性突触潜力的时间介入，这些活动形式与大胆反映的认知之间的关系。因此，必须检查某些形式的神经活动，粗体与认知过程的参与之间的对应关系。例如，在某些情况下，负大胆信号需要细微的解释。 fMRI的减法性最初表明，负大胆只是反映了基线期间的激活增加。但是，许多发现表明负粗体表示一个独特的现象。该提议的重点是研究与认知相关的神经活动中负大胆反映的降低的证据。将使用先前显示出可靠停用的任务进行BOLD和CBF的校准MR测量。这些MR的流量和氧合测量将用于确定相对CMRO2和氧气提取，以充分评估BOLD的生理基础。与MR度量相比，将记录多个频带中的EEC和EEC功率。在要使用的任务中表征EEC的变化已经进行了许多工作，但是很少尝试将EEC与MR信号联系起来。这项工作将洞悉认知任务中MR信号变化之间的关系，而EEC则按表面和有限数量的患者，硬膜下电极进行了变化。