Coding advantage of grid cell orientation under noisy conditions

Abstract

Grid cells constitute a crucial component of the "GPS" in the mammalian brain. Recent experiments revealed that grid cell activity is anchored to environmental boundaries. More specifically, these results revealed a slight yet consistent offset of 8 degrees relative to boundaries of a square environment. The causes and possible functional roles of this orientation are still unclear. Here we propose that this phenomenon maximizes the spatial information conveyed by grid cells. Computer simulations of the grid cell network reveal that the universal grid orientation at 8 degrees optimizes spatial coding specifically in the presence of noise. Our model also predicts the minimum number of grid cells in each module. In addition, analytical results and a dynamical reinforcement learning model reveal the mechanism underlying the noiseinduced orientation preference at 8 degrees. Together, these results suggest that the experimentally observed common orientation of grid cells serves to maximize spatial information in the presence of noise.

Neural Coding as a Statistical Testing Problem

“…Since their discovery in 2005 [11], which earned O'Keefe and the Mosers the Nobel Prize, grid cells have been intensively studied from a theoretical point of view in relation to place cells [19]. Some authors (see for example [21]) are interested in how neural networks can generate such patterns, while others try to explain the hexagonal lattice [6] or the exact geometric progression of scales [27,23].…”