Grant: Doctoral Award - Frederick Banting and Charles Best Canada Graduate Scholarships

Brain lesions in the tissue responsible for transmitting brain signals that appear bright on magnetic resonance imaging (MRI) images are referred to as white matter hyper-intensities (WMH). They are found in 25% of healthy individuals over the age of 65 and have been linked to dementia. In the healthy population the number of WMH has little impact on a person's cognitive abilities, however if a patient has Alzheimer's Disease (AD) WMH appear to be very detrimental. We aim to investigate the differences in the structure and function of WMH, and to apply this knowledge to develop an MRI method that will be able to distinguish benign WMH from those that cause damage and a loss of cognitive function. To characterize the WMH we will study an animal model of AD in which we will induce brain lesions. The natural progression of the WMH will be studied using MRI, high frequency ultrasound imaging, coherent anti-Stokes Raman spectroscopy, and histology. Using these techniques we will look at the structure and damage of the white matter, it's physiological state, and the blood vessels supplying it. The changes in the WMH will be compared to the recovery of the animals cognitive function. By identifying which changes in the structure of the WMH are related to behavioral recovery in animals, we hope to develop an MRI method to identify those WMH that cause cognitive impairment. This novel MRI protocol will be tested on 20 subject at various points of AD progression, namely healthy, mild cognitive impairment, early AD, and AD.