Robyn Rutgers ’24
Researchers have long been interested in establishing how the brain remembers spatial environments and avoids confusion in similar environments, such as in a new supermarket. A recent study from University of Arizona researchers investigates how the processes of spatial memory retrieval are implemented in the brain and how the brain differentiates memory representations that involve overlapping features.
The study recruited 27 participants to view videos of three nearly identical cities each with seven stores — one store at the center of the city and six others spaced around the city. While the stores were found in the same location in every city, not every city had the same stores. The participants were asked to memorize the location of each store in each city, where the stores were in relation to each other, and how long it took to get from one store to another. Participants could replay the videos as many times as needed to achieve memorization.
Researchers measured patterns of participant brain activity through an MRI scanner, which took images of participants’ brains while researchers asked participants to recall information about the cities. Results showed that the patterns of brain activity when recalling each city were very similar to one another, as the cities were nearly identical. However, when participants recalled stores that appeared in more than one city, MRI scans indicated that participants’ brains were distinguishing the stores even more than stores that were completely different. Additionally, the MRI images suggest that the brain stores information on spatial environments specifically in the prefrontal cortex.
The findings of this study suggest that the brain treats similar environments with more distinction than environments that have little in common, a concept known as repulsion. Researchers suggest that repulsion is a process that allows our brains to learn distinct new information while avoiding relearning similar processes or experiences. The results of this study are important as they can help scientists to further understand conditions resulting in poor spatial memory, such as Alzheimer’s disease and strokes.
 L. Zheng, et al., Partially overlapping spatial environments trigger reinstatement in hippocampus and schema representations in prefrontal cortex. Nature Communications 12, 1-15 (2021). doi: /10.1038/s41467-021-26560-w.