Resting state connectivity: Biophysical basis for and improved fMRI measurements

主要研究者（最后，第一，中间）：克莱菲尔德，大卫和罗森，布鲁斯R。 功能性磁共振成像（fMRI）是推断脑内神经元活动的唯一手段。 整个人脑的体积。功能性磁共振成像的一个重要方面是关注大脑皮层的协调波动， 血氧水平依赖（BOLD）信号的振幅跨越大脑的远端区域， 被解释为“静止状态功能连接”。在这里，我们解决潜在的生物物理 这是一种基于静息态功能连接的机制。我们的假设是， 微动脉壁平滑肌中的超低频振荡，称为血管运动， - 中间振荡器，其将神经元活动中的振荡与血氧联系起来， 从而产生功能性磁共振成像信号。啮齿动物模型允许我们通过详细的双光子 成像，先进的功能磁共振成像测量，以及皮质血管动力学和血液的操纵 在受控条件下进行氧化。提高了超高场磁共振的空间分辨率 在人类中成像，以100微米或更高的分辨率对单个皮质内血管成像， 测试血管运动是否可能是静息和任务驱动的fMRI信号的统一机制。的 这些研究的结果有两个结果。一是为口译提供基础 相对于神经元投射的静息状态连接。二是新的测绘模式 通过改变小动脉体积的功能连接。特别是， 啮齿动物和灵长类动物的生理学表明，这些方法可以扩展到绘制静息- 以更高的分辨率和更高的精度来描述人类大脑中的功能连接， 以前实现的。这一新的机制见解将推动我们使用功能磁共振成像来研究认知， 各种神经精神疾病

Principal Investigators(Last, first, middle):KLEINFELD, DAVID and ROSEN, BRUCE R. Functional magnetic resonant imaging (fMRI) is the only means to infer neuronal activity within the entire volume of the human brain. A powerful aspect of fMRI concerns coordinated fluctuations in the amplitude of blood oxygen level dependent (BOLD) signals across distant regions of the brain, which are interpreted as "resting-state functional connections". Here we address the underlying biophysical mechanism that underlies resting-state functional connectivity. Our hypothesis is that the natural ultra-low frequency oscillations in the smooth muscle of arteriole walls, termed vasomotion, acts as an intermediate oscillator that links oscillations in neuronal activity with the blood oxygenation and thus fMRI signals. Rodent models permit us to test this hypothesis through detailed two-photon imaging, advanced fMRI measurements, and manipulations of cortical vascular dynamics and blood oxygenation under controlled conditions. We then advance the spatial resolution of ultra high field MR imaging in humans to image single intracortical vessels, with 100 micrometer or better resolution, to test whether vasomotion may be a unifying mechanism for resting and task-driven fMRI signals. The results of these studies have two consequences. One is to provide the underpinnings for interpreting resting state connectivity relative to neuronal projections. The second is a new model of mapping functional connections via changes in arteriole volume. In particular, the strong homologies between the physiology of rodents and primates suggest that these methods can be extended to map resting- state functional connections in the human brain with higher resolution and greater precision than previously achieved. This new mechanistic insight will advance our use of fMRI to study cognition and a variety of neuropsychiatric disorders.