Director-General Invited Seminar: ① Seong-Gi Kim, ② Jonathan Polimeni
日時
2023年09月11日(月)
①11：00～12:00 Seong-Gi Kim, ②14：00～15：00 Jonathan Polimeni
場所
生理学研究所1F セミナー室、 Zoom オンライン （ハイブリッド開催）
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使用言語
英語
演者
① Seong-Gi Kim （11：00～12：00）
Center for Neuroscience Imaging Research, Institute for Basic Science; Department of Biomedical Engineering,
Sungkyunkwan University Republic of Korea
② Jonathan Polimeni （14：00～15：00）
Athinoula A. Martinos Center for Biomedical Imaging; Department of Radiology,
Harvard Medical School; Massachusetts General Hospital
Title & Abstract
Seong-Gi Kim （11：00～12：00）
Title: Mapping somatomotor circuits with ultrahigh field fMRI in mouse and monkey
Abstract:
The somatomotor network is highly important for understanding the interaction between tactile and motor functions. Anatomical somatomotor connections have been investigated by viral tracing, but its functional circuits are not well-investigated especially in primates. Here we used whole-brain fMRI to identify the somatomotor network responding to somatosensory stimuli in anesthetized animals. Then, to separate upstream vs. downstream circuits, localized cortical regions were selectively activated or silenced. By combining fMRI with circuit manipulations, we were able to determine somatomotor circuits. In my talk, I will discuss microelectric and optogenetic stimulation, and share our recent 7T fMRI data in monkeys and 15.2T fMRI data in mice.
Jonathan Polimeni （14：00～15：00）
Title: High spatiotemporal resolution functional and physiological neuroimaging using Ultra-High Field MRI
Abstract:
Recent advances in MRI technology, including the current generation of clinically approved 7 Tesla scanners, have expanded the range of what can be measured with MRI, however challenges remain that prevent these technologies from reaching their full potential. In this lecture, I will first present several advanced "high-performance" acquisition methods, based on accelerated Echo Planar Imaging (EPI), that achieve high imaging resolution while being robust to artifacts to enable reliable, high-quality data across the entire brain at 7T. Then I will present applications of these technologies to functional mapping of the brain at the fine spatial scales of cerebral cortical columns and layers and new directions in the emerging field of "fast fMRI" that show how the BOLD response can track surprisingly fast neural dynamics. These studies and others indicate that the "biological resolution" of fMRI is intrinsically high, and that with further improvements in imaging resolution we will be able to extract more meaningful neuronally specific information from fMRI data. I will also present recent work imaging brain vasculature in vivo at 7T at unprecedented scales, and new biophysical models based on realistic microvascular anatomy and dynamics that can be used to better interpret the fMRI signals. I will summarize our work applying these methods to measure and characterize cerebrovascular physiology, including reduced vascular reactivity in neurological disease. I will conclude by presenting our recent, ongoing work measuring CSF flow dynamics, driven by the vasculature, across the entire brain at 7T in order to observe the brain's "glymphatic" or waste clearance system in action both in health and disease.