Event structure sculpts neural population dynamics in the lateral entorhinal cortex

Abstract

Our experience of the world is a continuous stream of events which must be segmented and organized simultaneously at multiple timescales. The neural mechanisms underlying this process remain unknown. Here, we simultaneously recorded many hundreds of neurons in the lateral entorhinal cortex (LEC) of freely behaving rats as we manipulated event structure at multiple timescales. During foraging as well as during sleep, population activity drifted continuously and unidirectionally along a one-dimensional manifold. Boundaries between events were associated with discrete shifts in state space, suggesting that LEC dynamics directly reflect event segmentation. During tasks with a recurring temporal structure, activity traveled additionally in directions orthogonal to the flow of drift, enabling the LEC population to multiplex event information across different timescales. Taken together, these results identify a hierarchically organized neural coding scheme for segmenting and organizing events in time.