In Vivo Measurements of Physiologically-evoked Neuronal Currents

描述（由申请人提供）：本项目的目标是使用章鱼作为体内动物模型，以探索MRI直接检测正常感觉刺激诱发的神经元电流的能力。原则上，神经元电流MRI（ncMRI）提供了比当前基于血流动力学的功能性MRI方法更高的时空分辨率。然而，关于在人类受试者中检测ncMRI信号的矛盾报告使ncMRI的可行性成为一个悬而未决的问题。由于大多数先前的人类ncMRI研究由于无法分离或消除血液动力学效应而存在问题，因此尚未得出ncMRI是否可实现的结论。为了令人信服地解决这个长期存在的争论，我们将检测章鱼中视觉诱发的ncMRI信号。章鱼有一个大的大脑和高度发达的视觉系统，但它的血液不产生任何血氧水平依赖（BOLD）的对比度。因此，它是一个理想的体内动物模型，用于测量ncMRI无BOLD污染。拟议的ncMRI是一项旨在直接对神经元电流进行成像的创新技术。通过将神经元中的电生理事件与常规MRI技术提供的大型神经元群体的系统级视图相连接，它应该具有很高的影响。该研究项目的成功开发将解决关于ncMRI可行性的长期争论。具体来说，任何ncMRI信号的检测将使我们能够，第一次，描述神经元电流成像的时间和空间特性。反过来，这些测量将为未来人类ncMRI实验的采集策略和解释提供必要的基础。

DESCRIPTION (provided by applicant): The goal of this project is to use octopus as an in vivo animal model to explore the ability of MRI to directly detect the neuronal electrical currents evoked by normal sensory stimulation. In principle, neuronal current MRI (ncMRI) offers improved spatio-temporal resolution over current hemodynamic-based functional MRI methods. However, contradictory reports regarding the detection of ncMRI signal in human subjects have left the feasibility of ncMRI an open question. Since most previous human ncMRI studies are problematic due to their inability to separate or eliminate hemodynamic effects, no conclusion is yet been possible whether ncMRI is achievable. To resolve this long-standing debate convincingly, we will detect visually evoked ncMRI signals in the octopus. The octopus has a large brain and a highly developed visual system, but its blood does not produce any blood oxygen level dependent (BOLD) contrast. Therefore, it is an ideal in vivo animal model for measuring ncMRI without BOLD contamination. The proposed ncMRI is an innovative technology that aims to image neuronal electrical currents directly. It should have a high impact by connecting the electrophysiological events in neurons with the systems-level view of large neuronal populations afforded by conventional MRI techniques. Successful development of this proposed research project will resolve the long-standing debate on the feasibility of ncMRI. Specifically, detection of any ncMRI signal will enable us, for the first time, to describe the temporal and spatial characteristics of neuronal current imaging. These measurements, in turn, will provide the necessary foundation for acquisition strategies and interpretations of future human ncMRI experiments.