Neuron-Powered Navigation: How Spatial Memory Helps Guide Us
Many of our memories revolve around important events that occurred at particular times and places. Such memories are recalled later to guide our decisions as we navigate familiar environments, or they can be used to help us make our best guess about how to get around a new environment. For example, you might learn that the best restaurants are located on the corners of blocks in one city. When you visit a different city for the first time, you might generalize what you’ve learned and assume that you’ll find the best restaurants on the corners of the new city. My research on spatial memory and goal-directed navigation seeks to understand how neurons of the brain work together to build a rich tapestry of memories that allow us to not get lost in familiar environments, and to quickly learn about, and navigate to, important locations in a new environment.
By studying the memory problems of people with different types of brain damage, we know that the hippocampus is a key part of our brain that is critical for our ability to learn about new events and places. This is likely tied to the fact that with experience, many hippocampal cells (called place cells) come to represent the meaning of specific locations (called place fields) within an environment. Different hippocampal neurons represent different locations so that the hippocampus can consider all important information in a given environment. Remarkably, the meaning of different locations can change as new information emerges, and this is how the information represented in the hippocampus stays current. I would like to figure out how the hippocampus uses place field information to create and update our memories. Also, I am studying what types of information are used to form place fields so that we might someday be able to improve specific forms of learning and memory.
People with hippocampal damage also have difficulty imagining the future. This suggests that the hippocampus processes not only spatial information but temporal information as well. Recent studies suggest that if I were to stand in one place and imagine walking forward toward a candy bar across the room, my hippocampal place cells will become active in a temporal sequence that matches the order of the place fields that I am about to enter. That is, the hippocampus somehow organizes place field information in advance of my actions, as if it is planning my future! Have we figured out the neural basis of imagination? Probably not, but we can say that the hippocampus likely contributes to our ability to make future plans about how to get to where we want to go.
Learn more about Dr. Mizumori’s research in the exhibit Memory: Past Meets Present that runs September 17, 2016 through March 5, 2017.
Portal to Current Research is an exhibit that showcases local scientists’ advances in current research through a combination of digital media, graphics, objects, and interactive displays and programs. Exhibits change twice a year. In the current exhibit, Memory: Past Meets Present, investigate how we acquire, consolidate, and retrieve our memories, and focus on spatial memory: memories about where things are. Challenge your memory skills by testing a technique used by ancient Greeks and Romans to memorize epic poems, or play a touch-table game about foraging for food in a forest. Learn about current research from the University of Washington that sheds light on how our brains record spatial information that also may help scientists develop a diagnostic tool to detect early warning signs of Alzheimer’s disease. This installment of Memory: Past Meets Present will be on display in the Portal to Current Research through March 5, 2017.