Studying Dynamic Blood Flow/Metabolism Regulation in the Brain

大脑消耗的能量比人体其他任何器官都多，尽管体重不到身体重量的2%，但大脑仍占每日能量摄入量的20%，令人震惊。此外，大脑没有能量储存，因此它依赖微调的血液流动来提供持续的燃料供应(即氧气和葡萄糖)。血液流量的调整在整个大脑中发生，因为局部能量消耗不断变化，以适应大脑活动的变化。血液流动、能量消耗和大脑活动之间的紧密耦合导致人们认识到，适当控制血液流动对大脑健康至关重要。脑血管阻塞或破裂引起的中风就是这种依赖性的戏剧性证明，因为损伤可能在几分钟内发生。然而，有一种思路认为，血流控制的更细微变化可能会阻碍局部大脑活动对氧气和葡萄糖的充分输送，从而导致阿尔茨海默氏症等与年龄相关的疾病。由于这些变化是微妙的，其后果可能需要数年甚至数十年才能显现。 为了更好地理解这一动态过程，该研究计划专注于开发一种基于光的设备，以测量大脑活动变化期间血流与能量消耗的耦合。这些方法使用可见光以外的光，因为这种光能够在组织中传播得更远，这使得基于头皮的探测器可以测量大脑活动。这项技术极其安全、廉价和多功能(即可以在任何数量的活动期间监测大脑活动，如锻炼)。我们的目标是结合两种基于光的方法，提供大脑功能的互补信息：一种是对氧气使用敏感，另一种是测量血流量。我们的愿景是，这些方法协同工作将提供丰富的数据集，以开始了解血流控制的细微变化如何影响大脑的能量需求，以及这些变化是否可以与可能的年龄相关问题联系在一起，如认知能力下降。这个项目的目标是，首先证明这些基于光的方法可以提供准确的测量，然后使用这些方法来研究在大脑挑战期间对流动和氧气输送有不同影响的流动和能量消耗的耦合。

The brain uses more energy than any other organ in the human body, accounting for a staggering 20% of the daily energy intake despite weighting less than 2% of the body's weight. In addition, the brain has no energy stores so it relies on fine-tuning of blood flow to deliver a continuous supply of fuel (i.e., oxygen and glucose). Adjustments to blood flow occur regionally throughout the brain as local energy consumption is constantly changing to match variations in brain activity. This tight coupling between blood flow, energy consumption and brain activity has lead to the recognition that proper control of blood flow is critical to brain health. Stroke caused by a blocked or rupture blood vessel in the brain is a dramatic demonstration of this dependency as damage can occur in a matter of minutes. However, there is a line of thought that more subtle changes to blood flow control may contribute to age-related diseases such as Alzheimer's by hindering adequate delivery of oxygen and glucose in response to local brain activity. As these changes are subtle, the consequences could take years or even decades to manifest. To better how understand this dynamic process, this research program is focused on developing a light-based device to measure the coupling of blood flow to energy consumption during changes in brain activity. These methods use light outside of the visible range because this light is able to travel much farther through tissue, which allows brain activity to be measured by detectors based on the scalp. The technology is extremely safe, inexpensive, and versatile (i.e. brain activity can be monitored during any number of activities, such as exercise). Our goal is to combine two light-based methods that provide complementary information of brain function: one is sensitive to oxygen use, while the other measures blood flow. It is our vision that these methods working together will provide a rich data set to begin understanding how subtle changes in blood flow control can impact the brain's energy needs and if these changes can be linked to possible age-related issues such as cognitive decline. The goals of this program are centred on first showing that these light-based methods can provide accurate measurements and second using these methods to investigate the coupling of flow and energy consumption during brain challenges with different effects on flow and oxygen delivery.