Spatial navigation in rodents has been attributed to place-selective cells in the hippocampus and entorhinal cortex. However, there is currently no consensus on the neural mechanisms that generate the place-selective activity in hippocampal place cells or entorhinal grid cells. Given the massive input connections from the superficial layers of the entorhinal cortex to place cells in the hippocampal cornu ammonis (CA) regions, it was initially postulated that grid cells drive the spatial responses of place cells. However, recent experiments have found that place cell responses are stable even when grid cell responses are severely distorted, thus suggesting that place cells cannot receive their spatial information chiefly from grid cells. Here, we offer an alternative explanation. In a model with linear grid-to-place-cell transformation, the transformation can be very robust against noise in the grid patterns depending on the nature of the noise. In the two more realistic noise scenarios, the transformation was very robust, while it was not in the other two scenarios. Although current experimental data suggest that other types of place-selective cells modulate place cell responses, our results show that the simple grid-to-place-cell transformation alone can account for the origin of place selectivity in the place cells.
Keywords: feedforward networks; hippocampus; medial entorhinal cortex; neural networks; spatial representation.
© 2014 Wiley Periodicals, Inc.