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

It has long been thought that spatial memory relies on a structure in the brain, the hippocampus (HC), but it is becoming clear that some aspects of spatial memory can be spared following damage to this structure. It has been found that some patients with damage to the HC are still able to navigate in familiar environments that they learned long ago, prior to the damage to the HC. However, these patients might differ from healthy adults in their experience of the environment. It seems that they are able to remember schematic, map-like, aspects of environments that are sufficient for navigation, but they may not be able to remember more detailed aspects of the environment, such as what landmarks look like. It is possible that the schematic aspects of spatial memory may rely on a different part of the brain, other than the HC. One possibility is a region called the lateral temporal cortex, which is deteriorated or damaged in individuals with Semantic Dementia (SD).To examine this possibility, we will be testing individuals with SD on navigation tasks designed to assess memory for familiar environments learned long ago (remote spatial memory) for distance, direction, routes, and landmark appearance. To control for dementia, patients with Alzheimers Disease (AD), who, unlike SD patients, typically have damage to the HC, will also be tested. It is possible that SD patients may lack the schematic aspects of the environment that would allow them to navigate in an old environment. By investigating remote spatial memory in both patients with SD and AD, we may be able to distinguish between these forms of dementia at early stages.It will also help us understand the areas of the brain that are important for different types of memory. Understanding which types of memory are preserved and damaged in these types of dementias is important for the long term goal of developing intervention strategies that make use of the intact abilities and help to remediate the impaired abilities.