OCULAR DOMINANCE COLUMN MAPPING IN HUMAN V1 USING FMRI

使用 FMRI 绘制 HUMAN V1 中的眼优势列图

基本信息

批准号：
2711198
负责人：
RAVI S MENON
金额：
$ 9.42万
依托单位：
JOHN P. ROBARTS RESEARCH INSTITUTE
依托单位国家：
美国
项目类别：
财政年份：
1996
资助国家：
美国
起止时间：
1996-09-01 至 2000-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/2711198
关键词：
bioengineering /biomedical engineering brain mapping clinical biomedical equipment functional magnetic resonance imaging human subject method development visual cortex

项目摘要

DESCRIPTION: Functional Magnetic Resonance Imaging (fMRI) has rapidly become a desirable neuroimaging tool for cognitive scientists and clinicians, because of the tremendous advantage of non-invasively assessing human brain function. Hundreds of successful initial fMRI studies on clinical MRI machines have used robust paradigms which elicit measurable signal changes at modest image resolution. However, there exists considerable controversy over the ultimate spatial resolution and functional specificity of the BOLD technique, because neither the underlying mechanisms of the cerebral vascular response nor their effect on the BOLD signal are understood. Therefore, the investigators' objective is to establish the specificity of the cortical vascular response to well defined units of neuronal activity, as well as determine the sensitivity of fMRI to BOLD changes in such basic units of cortical organization. This should allow the extension of fMRI techniques to the level of coarse electrophysiology in humans. In this grant, the investigators propose to develop techniques necessary to image ocular dominance columns in the human visual system. These columns form an unique and ideal in-vivo resolution system for fMRI since they constitute point sources of neuronal activation that can be driven by a simple paradigm. The investigators' hypothesis, for which they will present preliminary supporting evidence, is that fMRI can be performed at the resolution of coarse electrophysiological measurements. This implies that the vascular response is appropriately localized to functional subunits. In order to test this hypothesis, the investigators will develop methods to (1) increase image SNR using ultra-high field fMRI and phased array coils to the point that thermal (Johnson) noise is not the dominant source of image-to-image fluctuations in high resolution images, (2) assess in a quantitative statistical manner the degree to which the brain and body motions and instrumental instabilities contribute to the remaining inter-image fluctuations by studying signal magnitude and phase in consecutively acquired fMRI images using several different imaging pulse sequences and (3) develop new hardware and software strategies for the compensation of the quantities underlined in (2) in order to reduce the remaining image-to-image fluctuations and consequently reduce the detection threshold for high resolution cortical mapping using fMRI.

描述：功能磁共振成像（fMRI）迅速成为认知科学家的理想神经影像学工具临床医生，由于非侵入性评估的巨大优势人脑功能。关于数百项成功的初始fMRI研究临床MRI机器使用了可衡量可测量的稳健范例信号以适中的图像分辨率变化。但是，存在关于最终的空间分辨率和功能的极大争议大胆技术的特异性，因为没有基本机制大脑血管反应或它们对粗体信号的影响是理解。因此，调查人员的目标是建立皮质血管反应的特异性对明确定义的单位的特异性神经元活性，并确定fMRI对BOLD的敏感性皮质组织的基本单位的变化。这应该允许 fMRI技术扩展到粗大的电生理水平人类。在这笔赠款中，调查人员建议开发技术在人类视觉系统中成像眼部优势列所必需的。这些列构成了fMRI的独特而理想的体内分辨率系统由于它们构成了可以是神经元激活的点源由简单的范式驱动。调查人员的假设，他们为此将提供初步支持证据，是可以执行fMRI 在分辨出粗大的电生理测量值时。这意味着血管反应适当地定位于功能亚基。为了检验这一假设，研究人员将发展（1）使用超高场fMRI和分阶段增加图像SNR的方法阵列线圈，以至于热（约翰逊）噪声不是主要的高分辨率图像中图像到图像波动的来源，（2）评估以定量统计方式大脑和身体的程度动作和工具不稳定性有助于其余通过研究信号幅度和相位的形象间波动使用几个不同的成像脉冲连续获取fMRI图像序列和（3）开发新的硬件和软件策略（2）中下划线的数量的补偿，以减少剩余的图像到图像波动，因此减少了检测使用fMRI的高分辨率皮质映射的阈值。