RT Journal Article
SR Electronic
T1 Fragmented Spatial Maps: State Abstraction and Efficient Planning from Surprisal
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2021.10.29.466499
DO 10.1101/2021.10.29.466499
A1 Mirko Klukas
A1 Sugandha Sharma
A1 YiLun Du
A1 Tomas Lozano-Perez
A1 Leslie Kaelbling
A1 Ila Fiete
YR 2021
UL http://biorxiv.org/content/early/2021/11/01/2021.10.29.466499.abstract
AB When animals explore spatial environments, their representations often fragment into multiple maps. What determines these map fragmentations, and can we predict where they will occur with simple principles? We pose the problem of fragmentation of an environment as one of (online) spatial clustering. Taking inspiration from the notion of a contiguous region in robotics, we develop a theory in which fragmentation decisions are driven by surprisal. When this criterion is implemented with boundary, grid, and place cells in various environments, it produces map fragmentations from the first exploration of each space. Augmented with a long-term spatial memory and a rule similar to the distance-dependent Chinese Restaurant Process for selecting among relevant memories, the theory predicts the reuse of map fragments in environments with repeating substructures. Our model provides a simple rule for generating spatial state abstractions and predicts map fragmentations observed in electrophysiological recordings. It further predicts that there should be “fragmentation decision” or “fracture” cells, which in multicompartment environments could be called “doorway” cells. Finally, we show that the resulting abstractions can lead to large (orders of magnitude) improvements in the ability to plan and navigate through complex environments.Competing Interest StatementThe authors have declared no competing interest.