fMRI ABILITY TO MAP COLUMNAR STRUCTURES IN HUMANS

描述（由申请人提供）： 功能性磁共振成像提供了无与伦比的空间和时间分辨率的组合，并将继续推向新的水平。最近，BOLD功能磁共振成像的极限受到了挑战，亚毫米结构的水平。这些地图的可靠性和可重复性，以及功能磁共振成像方法的优化，以获得这些地图尚未建立，特别是在人类。使用梯度回波的差分标测在一般情况下可能不可靠，因为众所周知的大血管伪影（在低场更明显），已用于人体。我们最近已经证明了，通过R21提案的资助，在亚毫米空间分辨率下，高场哈恩自旋回波（HSE）BOLD信号的优势。GE和HSE BOLD信号在高场强下对神经活动的特异性差异尚未得到解决。映射大脑功能的优化BOLD信号可以允许在没有正交条件的先验知识的情况下映射功能架构（即，单一条件映射）。这将是一个宝贵的工具，为许多神经科学的应用，正交条件和柱状组织一般是未知的。这项工作将推进我们以前的R21建议的基础上，研究T2加权功能磁共振成像在高磁场。本申请的中心假设是，在高场（7特斯拉）下基于HSE的BOLD fMRI信号可以用于获得更高的空间特异性，因此在清醒的人类中，比在较低场（4特斯拉）和/或具有梯度回波的情况下更可靠的皮质柱图。最后，在人类中存在的方向柱，这从来没有被证明，可以解决使用功能磁共振成像技术在这项工作中开发。

DESCRIPTION (provided by applicant): Functional magnetic resonance imaging offers an unmatched combination of spatial and temporal resolution that continues to be pushed to new levels. Recently, the limits of BOLD fMRI have been challenged to the level of sub-millimeter structures. The reliability and reproducibility of these maps, as well as the optimization of the fMRI methods to acquire these maps has not yet been established, especially in humans. Differential mapping using gradient echoes, which may not be reliable in the general case because of the well known large vessel artifacts (more significantly at low fields), has been used in humans. We have recently demonstrated, made possible by funding from an R21 proposal, at sub-millimeter spatial resolutions, the advantages of high field Hahn spin echo (HSE) BOLD signals. Differences in specificity to neural activity between GE and HSE BOLD signals at high fields has not yet been addressed. Optimized BOLD signals to map brain function could allow for mapping of functional architecture without apriori knowledge of orthogonal conditions (i.e. single condition mapping). This would be an invaluable tool for many neuroscience applications where orthogonal conditions and columnar organizations in general are not known. This work will advance the foundation of our previous R21 proposal which investigated T2 weighted fMRI at high magnetic fields. The central hypothesis of this application is that HSE based BOLD fMRI signals at high fields (7 Tesla) can be used to attain a higher spatial specificity and therefore more reliable maps of cortical columns, in awake humans, than at lower fields (4 Tesla) and/or with gradient echoes. Finally, the existence of orientation columns in humans, which has never been shown, can be addressed using fMRI techniques developed in this work.