A neural code for egocentric spatial maps in the human medial temporal lobe

Abstract

Spatial navigation relies on neural systems that encode information about places, distances, and directions in relation to the external world or relative to the navigating organism. Since the proposal of cognitive maps, the neuroscience of navigation has focused on allocentric (world-referenced) neural representations including place, grid, and head-direction cells. Here, using single-neuron recordings during virtual navigation, we identify "anchor cells" in the human brain as a neural code for egocentric (self-centered) spatial maps: Anchor cells represent egocentric directions towards "anchor points" located in the environmental center or periphery. Anchor cells were abundant in parahippocampal cortex, supported full vectorial representations of egocentric space, and were integrated into a neural memory network. Neurons encoding allocentric direction complemented anchor-cell activity, potentially assisting anchor cells in transforming percepts into allocentric representations. Anchor cells may facilitate egocentric navigation strategies, may support route planning from egocentric viewpoints, and may underlie the first-person perspective in episodic memories.