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要多，尽管它的重量不到身体重量的2%，但它却占每日能量摄入的惊人20%。此外，大脑没有能量储存，所以它依赖于血液流动的微调来提供持续的燃料供应（即氧气和葡萄糖）。随着局部能量消耗不断变化以适应大脑活动的变化，血流的调整在整个大脑区域发生。血流量、能量消耗和大脑活动之间的紧密耦合使人们认识到，适当控制血流量对大脑健康至关重要。脑内血管阻塞或破裂引起的中风是这种依赖性的一个戏剧性的证明，因为损伤可能在几分钟内发生。然而，有一种观点认为，血流控制的更细微变化可能会导致与年龄相关的疾病，如阿尔茨海默氏症，因为局部大脑活动阻碍了足够的氧气和葡萄糖的输送。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出来。******为了更好地理解这一动态过程，该研究项目专注于开发一种基于光的设备，以测量大脑活动变化过程中血流量与能量消耗的耦合。这些方法使用可见光范围之外的光，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。这项技术非常安全、廉价且用途广泛（即可以在任何活动期间监测大脑活动，例如运动）。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：一种是对氧气的使用敏感，而另一种是测量血流量。我们的愿景是，这些方法一起工作将提供丰富的数据集，以开始了解血液流动控制的细微变化如何影响大脑的能量需求，以及这些变化是否与可能的年龄相关问题（如认知能力下降）有关。这个项目的目标首先集中在展示这些基于光的方法可以提供准确的测量，其次使用这些方法来研究大脑挑战过程中流量和能量消耗的耦合，以及对流量和氧气输送的不同影响。

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.