BME MS Thesis Defense: Megan Bell

Title: "Flexible Neural Representations of Interpersonal Distance in the Human Medial Temporal Lobe"

Advisory Committee: Chair: Xue Han, Members: Matthias Stangl and Kamal Sen

Abstract: Everyday social tasks require humans to represent not only their surroundings, but the locations of people within these surroundings as well. Current knowledge of neural representations of self and others is based largely on research in non-human animals. It remains unknown how humans integrate others into their cognitive maps and create representations of interpersonal distances. To address this gap, we studied individuals with chronically implanted intracranial electrodes while they participated in social observation tasks. Participants observed two walkers within a room and were instructed to focus on the distance between themselves and one walker at a time (self-other distance) or the distance between the two walkers (other-other distance). The results show that neural representations in the medial temporal lobe (MTL) – a critical region for spatial navigation and memory – are modulated by self-other and other-other distance. These representations are also dependent on the focus of the participant, with only the distance that the participant is actively tracking being represented at any given time. These results support the growing body of knowledge regarding the representations of other people in our cognitive maps and demonstrate the flexibility of the MTL in representing different features depending on one's cognitive state. This work uses novel methods to study human cognition in naturalistic environments and gain insight into the neural mechanisms that allow us to integrate others into our cognitive map in real-world situations.