fMRI and patient studies of remote spatial and episodic memory

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Remembering past personal experiences (episodic memory) and how to get around in our home or neighbourhood (spatial memory) are both crucial for daily life. Without episodic memory, we are unable to re-experience our most cherished moments or to recall critical information that may be necessary to everyday function; without spatial memory, we literally would be lost. This proposal is concerned with how these types of memories relate to one another and how they are represented in the brain. Our ability to learn and retain new episodic and spatial memories depends on the hippocampus, a structure deep in the temporal lobes: damage to the hippocampus impairs memory for recently experienced events and spatial environments. My trainees and I showed that very old (remote) episodic and spatial memories that are highly detailed and precise continue to depend on the hippocampus, and that its role extends beyond memory to include imagining of detailed future episodes. In contrast, more schematic remote spatial memories (skeletal "maps" of major roads and landmarks) do not seem to depend on the hippocampus and instead rely on other brain structures, such as parietal cortex. ***The goal of the current proposal is to extend these findings by taking a novel approach of scanning experts and patients with selective brain lesions using functional magnetic resonance imaging (fMRI), a technique that allows visualization of on-line brain activity (blood flow) as participants perform the various tasks. Study 1 will involve scanning a unique population of experts, birdwatchers, who keep journals of the time and spatial location of birds that they have encountered in the past. Journals also serve as a record of birds that have not yet been encountered, allowing us to directly compare the role of the hippocampus in temporal vs. spatial aspects of episodic memories and in future imagining of bird sightings. Study 2 involves scanning patients with lesions to the hippocampus or parietal cortex. These two groups have different memory profiles that allow for the study of different components of spatial memory. This study includes an innovative software suite designed around Google Street View that can produce simulations of real-world spatial environments to track moment-by-moment involvement of different brain regions during virtual navigation along routes that are novel or familiar, or when changes to familiar routes are introduced.***Canada has a rich history in the area of cognitive neuroscience and is regarded as an international leader in memory research. It is important to maintain this status through the specialized training of students in developing basic theory and effective applications of innovative technologies such as fMRI for examining brain function and virtual reality. Findings will lead to a greater understanding of the cognitive makeup of different types of memory and how they are represented in the human brain. **