Depth-dependent fMRI: feasibility and utility

深度依赖性功能磁共振成像：可行性和实用性

• 批准号: 9033517
• 负责人: Cheryl A. Olman
• 金额: $ 22.8万
• 依托单位: UNIVERSITY OF MINNESOTA
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-02-03 至 2018-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9033517
• 关键词: Affect; Agreement; Attention; Autistic Disorder; Awareness; Behavior; Behavioral; Biological Neural Networks; Blood Vessels; Blood capillaries; Brain; Brain region; Characteristics; Clinical; Code; Cognition; Cognitive; Color; Complex; Conflict (Psychology); Contrast Sensitivity; Data; Development; Disease; Dyslexia; Electrodes; Electrophysiology (science); Equilibrium; Equipment; Eye; Feedback; Foundations; Frequencies; Functional Magnetic Resonance Imaging; Functional disorder; Geometry; Grouping; Human; Image; Interneurons; Learning Disabilities; Literature; Maps; Measurement; Measures; Methods; Monitor; Neural Network Simulation; Neurons; Neurosciences; Output; Pathway interactions; Pattern; Perception; Physiologic pulse; Physiological; Play; Population; Process; Property; Protocols documentation; Publications; Reporting; Research; Research Personnel; Resolution; Rest; Role; Sampling; Schizophrenia; Series; Signal Transduction; Source; Specific qualifier value; Specificity; Stimulus; Structure; Synapses; Techniques; Testing; Texture; Thick; Visual; Visual Fields; Width; Work; area striata; capillary; capillary bed; cytochrome c oxidase; density; design; feeding; gray matter; in vivo; magnocellular; millimeter; nervous system disorder; neural correlate; neuroimaging; neuromechanism; neurotransmission; orientation columns; orientation selectivity; parvocellular; programs; public health relevance; radio frequency; relating to nervous system; research study; response; segregation; technological innovation; vision science; visual information; visual stimulus

ABSTRACT Functional magnetic resonance imaging (fMRI) is undeniably the workhorse for neuroscientists who want localized measurements of neural correlates of human behavior. However, recent studies have presented fMRI results that conflict with traditional invasive (direct) electrophysiological measurements of neural population responses: attention strongly modulates the fMRI response in primary visual cortex (V1) but only weakly modulates neural firing rates; fMRI responses in V1 predict perceptual states while only subtle aspects of direct recordings of V1 neural responses correlate with perception. An important step toward reconciling the differences between fMRI data and invasive electrophysiology is to obtain fMRI data that can map out the details of the local neural population code on a scale that is closer to that sampled by electrodes. The proposed experiments will use 7 Tesla fMRI with sub-millimeter resolution – a spatial scale comparable to that of the local field potential in electrophysiology – to determine how the spatial details of the neural population response in V1 depend on visual stimulus properties as well as perceptual state. Because input, output and local connections are segregated according to depth, the primary focus of this research is to dissociate signals at different cortical depths. Several recent literature reports show that the fMRI response amplitude is different at different cortical depths. However, it is not yet established whether depth-dependent fMRI actually reflects local neural network changes at different cortical depths. The following aims seek to verify that fMRI has differential laminar sensitivity that corresponds meaningfully to neural activity. The first aim is to validate layer-specific fMRI against known properties of the intrinsic neural network. While fMRI and electrophysiological measurements of V1 response modulation due to behavioral or perceptual processes (putative feedback processes) disagree, there has been ample demonstration of the agreement between fMRI and electrophysiological measurements of intrinsic neural responses such as contrast sensitivity or orientation selectivity. Two sets of experiments will therefore quantify the depth-dependent fMRI response to simple visual stimuli, validating the fMRI laminar profile against laminar profiles predicted by electrophysiology. The second aim is to study modulation of neural responses in V1 by visual information that is extracted over a larger spatial scale. Enhancement of V1 neural responses by global scene structure (figure/ground segmentation) and suppression of V1 neural responses by uniform texture (orientation-dependent surround suppression) differ importantly in the role of awareness in regulating the modulation in V1. We will quantify fMRI laminar profiles under these two different kinds of contextual modulation. Because both visual feature grouping and iso-orientation suppression are affected by neurological disorders such as autism and schizophrenia, validating a technique for monitoring these mechanisms of visual contextual modulation has utility in the clinical setting.

抽象的 功能磁共振成像（fMRI）无疑是神经科学家的主力 想要人类行为的神经元相关性的局部测量。但是，最近的研究提出了 fMRI结果与神经元的传统侵入性（直接）电生理测量相冲突 人口反应：注意力强烈调节原代视皮（V1）中的fMRI响应 弱调节神经发射率； V1中的fMRI响应预测感知状态，而只有微妙的方面 V1神经的直接记录与感知相关。迈向和解的重要一步 fMRI数据和侵入性电生理学之间的差异是获取可以绘制绘制的fMRI数据 局部神经种群代码的详细信息范围更接近电极采样的范围。 拟议的实验将使用7种特斯拉fMRI和亚毫米分辨率 - 一种与之相当的空间量表 电生理学的局部现场潜力 - 确定神经人口的空间细节如何 V1中的响应取决于视觉刺激特性以及感知状态。 因为输入，输出和本地连接是根据深度隔离的，所以 这项研究是在不同的皮质深度分离信号。最近的一些文献报告表明 fMRI响应放大器在不同的皮质深度不同。但是，尚未确定是否是否 深度依赖性fMRI实际上反映了不同皮质深度的局部神经网络变化。下列 旨在验证fMRI具有差异层流灵敏度，与神经活动有意义相对应。 第一个目的是验证层特异性fMRI，以针对内在神经网络的已知特性进行验证。 而fMRI和由于行为或感知引起的V1响应调制的电生理测量值 流程（推定的反馈流程）不同意，该协议已经充分证明 fMRI和固有神经调查的电生理测量（例如对比度灵敏度） 或方向选择性。因此 简单的视觉刺激，验证了通过电生理学预测的层流谱的fMRI层流谱。 第二个目的是通过提取的视觉信息研究V1中神经反应的调制 超过更大的空间量表。通过全球场景结构增强V1神经调查的增强（图/地面 分割）和通过均匀纹理（依赖于方向的周围构成）抑制V1神经调查 抑制）在对V1中调节调制中的意识中的作用上有所不同。我们将量化 在这两种不同类型的上下文调制下，fMRI层状曲线。因为两个视觉功能 分组和同学抑制受自闭症和诸如自闭症和 精神分裂症，验证一种用于监视视觉上下文调制的机制的技术已有 临床环境中的实用程序。