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 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.