Grant: Discovery Grants Program - Individual

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 led to the recognition that proper control of blood flow and energy production are 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 subtle changes to blood flow control and diminished energy production may contribute to age-related diseases such as Alzheimer's. As these changes are subtle, the consequences could take years or even decades to manifest. This research program is focused on developing two light-based devices for studying blood flow regulation and metabolic efficiency in the human brain. These methods use light outside of the visible range because this light travels 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). As a marker of vascular health, our goal is to develop a highly sensitive device that can measure how fast the smallest of vessels in the brain, which is where oxygen exchange occurs, respond to increase brain activity. The second device will have the capability to directly measure the activity of the enzyme that controls oxygen consumption and how this enzyme activity changes with brain activity. Finally, this device will be combined with an imaging method known as positron emission tomography to study the relationship between this key enzyme, brain blood flow, oxygen and glucose consumption rates. Successful development of these technologies will provide a more comprehensive understanding of these key aspects of brain health. These technologies could used in future studies to study how their functions relate to healthy brain ageing.