Localized fMRI of heterogeneous neural responses

异质神经反应的局部功能磁共振成像

• 批准号: 8301873
• 负责人: Cheryl A. Olman
• 金额: $ 18.2万
• 依托单位: UNIVERSITY OF MINNESOTA
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-02-15 至 2014-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8301873
• 关键词: Access to Information; Accounting; Affect; Animal Model; Area; Automobile Driving; Behavior; Biological Markers; Biological Neural Networks; Brain; Characteristics; Code; Complex; Computer Simulation; Coupling; Data; Dependence; Detection; Disease; Equilibrium; Event; Exhibits; Functional Magnetic Resonance Imaging; Funding; Goals; Grant; Human; Image; Imaging Device; Individual; Link; Literature; Masks; Measurement; Measures; Methodology; Minority; Modeling; Neural Inhibition; Neurons; Neurophysiology - biologic function; Neurosciences; Output; Pattern; Perception; Physiological; Play; Population; Protocols documentation; Psychology; Publications; Reporting; Research Personnel; Resolution; Sampling; Schizophrenia; Scientist; Seizures; Series; Shapes; Signal Transduction; Source; Stimulus; Structure; Techniques; Testing; Theft; Time; Visual; Visual Cortex; Work; area striata; base; blood oxygen level dependent; blood oxygenation level dependent response; design; hemodynamics; improved; inhibitory neuron; innovation; interest; neural model; neural patterning; neuroimaging; relating to nervous system; research study; response; tool

DESCRIPTION (provided by applicant): Functional magnetic resonance imaging (fMRI) is undeniably the neuroimaging methodology that has become the workhorse for neuroscience and psychology researchers who want access to localized measurements of physiological changes in the brain that correlate with human behavior. The high value of fMRI measurements is based on the fact that they have been shown, time and again, to exhibit a linear correlation with the local neural population response. There are, however, a recent smattering of articles in the literature indicating a mismatch between the fMRI response and the measured or presumed neural activity. These mismatches appear limited to experiments in which only a small neural population is stimulated; they also seem most likely to occur when the balance between local neural excitation and inhibition is tipped in favor of inhibition. These reports of fMRI responses that fail to correlate with neural responses are puzzling at best, and potentially troublesome for scientists who want to draw quantitative conclusions about neural population activity from fMRI data. Our first series of proposed experiments will characterize the effects of sampling resolution on the interpretability of the fMRI response to small stimuli. Not only do flanking negative responses confound accurate interpretation of the fMRI response to small patches of neural activity, because the boundary regions are large compared to the total neural response, but size-dependent intrinsic inhibition shapes the neural response yet has an unknown representation in the hemodynamic response. The result of the first series of experiments will be a computational model characterizing (1) neuro-hemodynamic coupling at the edges of isolated patches of neural activity, and (2) the contribution of inhibitory neural activity to the fMRI response. Our second series of experiments will characterize fMRI response evoked by neural networks with different balances between excitation and inhibition. All local neural codes contain a balance between input and output; local computations use a balance of excitation and inhibition to shape the input and define output spiking rates. In this series of experiments, we will investigate the implications of our recent study showing that localized fMRI of individual image patches cannot be predicted simply from the responses of the neurons that respond best to those stimuli. Working with a computational model that demonstrates how the entire local neural population response can be used to predict fMRI responses, this second series of experiments will seek to identify signature hemodynamic response characteristics that are present when heterogeneous neural responses mask key information encoded in a sub-population of neurons. Together, these experiments will improve our ability to use high-resolution fMRI to characterize patterned neural activity, improving the utility of fMRI for clinicl applications such as neurosurgical planning and seizure locus detection. PUBLIC HEALTH RELEVANCE: Scientists who study the brain need high-resolution imaging tools in order to understand how different patterns of neural activity correlate with different aspects of behavior; functional magnetic resonance imaging (fMRI) is one of the tools that can provide the highest imaging resolution. However, we still need to answer some fundamental questions about the relationship between the fMRI signal and the underlying neural activity in the brain. The work funded by this grant will develop more accurate models for linking neural activity patterns to fMRI responses when (1) the neural response occupies only a small portion of cortex, and (2) sub- populations of neurons right next to each other have different responses. This ability to detect activity or dysregulation of activity in a subpopulation of neurons is key fr high-resolution localization of neural function, for neurosurgical planning or seizure locus detection, as well as for quantifying biomarkers of diseases such as schizophrenia, which differentially affects inhibitory neurons in visual cortex.

描述（由申请人提供）：功能性磁共振成像 (fMRI) 无疑是一种神经成像方法，已成为神经科学和心理学研究人员的主力，这些研究人员希望获得与人类行为相关的大脑生理变化的局部测量结果。 fMRI 测量值的高价值基于这样一个事实：它们已被一次又一次地证明与局部神经群体反应呈线性相关。然而，最近文献中的一些文章表明功能磁共振成像响应与测量或假设的神经活动之间不匹配。这些不匹配似乎仅限于仅刺激一小部分神经群的实验。当局部神经兴奋和抑制之间的平衡倾向于抑制时，它们似乎也最有可能发生。这些关于功能磁共振成像反应的报告与神经反应不相关，充其量是令人费解的，而且对于想要从功能磁共振成像数据中得出有关神经群体活动的定量结论的科学家来说，这可能会带来麻烦。 我们提出的第一系列实验将表征采样分辨率对 fMRI 对小刺激响应的可解释性的影响。侧翼阴性反应不仅会干扰对小块神经活动的功能磁共振成像反应的准确解释，因为与总神经反应相比，边界区域很大，而且大小依赖性的内在抑制塑造了神经反应，但在神经反应中具有未知的表示。血流动力学反应。第一系列实验的结果将是一个计算模型，其特征在于（1）神经活动孤立斑块边缘的神经血液动力学耦合，以及（2）抑制性神经活动对功能磁共振成像响应的贡献。 我们的第二系列实验将表征由兴奋和抑制之间具有不同平衡的神经网络引起的功能磁共振成像响应。所有局部神经代码都包含输入和输出之间的平衡；局部计算使用激励和抑制的平衡来塑造输入并定义输出尖峰率。在这一系列的实验中，我们将研究我们最近的研究的意义，该研究表明，不能简单地根据对这些刺激反应最好的神经元的反应来预测单个图像块的局部功能磁共振成像。通过使用一个计算模型来演示如何使用整个局部神经群体反应来预测功能磁共振成像反应，第二系列实验将寻求识别当异质神经反应掩盖了子神经元中编码的关键信息时出现的特征血流动力学反应特征。神经元群。 总之，这些实验将提高我们使用高分辨率功能磁共振成像来表征模式神经活动的能力，提高功能磁共振成像在神经外科规划和癫痫病灶检测等临床应用中的实用性。 公共健康相关性：研究大脑的科学家需要高分辨率成像工具，以便了解不同的神经活动模式如何与行为的不同方面相关；功能磁共振成像（fMRI）是可以提供最高成像分辨率的工具之一。然而，我们仍然需要回答一些关于功能磁共振成像信号与大脑潜在神经活动之间关系的基本问题。这项拨款资助的工作将开发更准确的模型，用于在以下情况下将神经活动模式与功能磁共振成像反应联系起来：（1）神经反应仅占据皮层的一小部分，（2）彼此相邻的神经元亚群具有不同的回应。这种检测神经元亚群活动或活动失调的能力是神经功能高分辨率定位、神经外科规划或癫痫位点检测以及量化精神分裂症等疾病生物标志物的关键，这些疾病对抑制性神经元有不同的影响在视觉皮层。