Points of contact between neuronal physiology and fMRI

神经元生理学和功能磁共振成像之间的联系点

• 批准号: 7121625
• 负责人: DAE-SHIK KIM
• 金额: $ 26.94万
• 依托单位: BOSTON UNIVERSITY MEDICAL CAMPUS
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-08-15 至 2008-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7121625
• 关键词: Points; contact; between; neuronal; physiology

DESCRIPTION (provided by applicant): Despite the fact that functional magnetic resonance imaging (fMRI) studies have become ubiquitous and are of ever increasing importance for clinical and basic neurosciences, the fundamental relationships between blood oxygenation level dependent (BOLD) and electrophysiological responses regarding spatial extent and amplitude are not well understood. Numerous BOLD studies at a coarse scale (several millimeter to centimeter) indicated a fair correlation between the foci of hemodynamic activity and the spatial localization of brain functions known from traditional single unit and lesion studies. However, the BOLD signal is not a direct measure of neuronal activity per se. Rather, it is a complex convolution of changes in cerebral metabolic rate of oxygen (CMR02), cerebral blood flow (CBF) and cerebral blood volume (CBV) following focal neuronal activity. Therefore, a direct and linear correlation between the amplitude of the observable BOLD signals and the underlying neural activity at the neurophysiologically important, sub-millimeter scale can therefore not be assumed a priori. In the present study, we suggest to address these questions in a direct manner. First, we propose to perform single/multi unit recording and BOLD fMRI from the same sites of the cat primary visual cortex using a novel "Cartesian grid" technique recently developed in our laboratory. Second, we will elucidate the contribution of spiking and subthreshold cortical activity in the observed BOLD contrast by carefully mapping the extraclassical versus classical receptive field boundaries. Third, neuroactive compounds that are known to influence the balance between excitatory and inhibitory cortical activity will be infused focally during functional MRI scans. In particular, the effect of GABA and bicuculline (CABALA antagonist) on the amplitude, time course, and spatial extend of BOLD signals will be tested. In summary, we believe that our project will provide pivotal insights into the fundamental points of contact between the observable, and ubiquitous BOLD contrast and its underlying neurophysiological origin.

描述(由申请人提供)： 尽管功能磁共振成像(FMRI)的研究已经变得无处不在，并且对临床和基础神经科学的重要性与日俱增，但血液氧合水平依赖(BOLD)与空间范围和幅度的电生理反应之间的基本关系仍未得到很好的了解。许多粗略规模(几毫米到厘米)的大胆研究表明，血流动力学活动的焦点与传统的单一单位和病变研究中已知的脑功能的空间定位之间存在良好的相关性。然而，大胆的信号并不是神经元活动本身的直接衡量标准。相反，它是局部神经元活动后脑氧代谢率(CMR02)、脑血流量(CBF)和脑血容量(CBV)变化的复杂卷积。因此，在神经生理学重要的亚毫米尺度上，可观察到的BOLD信号的幅度和潜在的神经活动之间的直接和线性相关性因此不能被假定为先验的。在本研究中，我们建议以直接的方式解决这些问题。首先，我们建议使用我们实验室最近开发的一种新的“笛卡尔网格”技术，从猫初级视觉皮质的相同位置进行单/多单位记录和BOLD fMRI。其次，我们将通过仔细绘制经典和经典接受野的边界来阐明棘波和阈值下皮层活动在观察到的大胆对比中的作用。第三，已知会影响兴奋性和抑制性皮质活动之间平衡的神经活性化合物将在功能磁共振扫描期间进行局部注射。特别是，将测试GABA和荷包牡丹碱(卡巴拉拮抗剂)对BOLD信号的幅度、时间进程和空间延伸的影响。总而言之，我们相信，我们的项目将为可观察的、无处不在的大胆对比与其潜在的神经生理学起源之间的基本接触点提供关键的见解。