Published on Wed Jul 14 2021

Learning spatio-temporal properties of hippocampal place cells

Lian, Y., Burkitt, A. N.

Hippocampal place cells generally respond to a single spatial position of a small environment. Grid cells in layer II of medial entorhinal cortex (MEC) also have spatio-temporal properties. EC is the upstream that projects strongly to the hippocampus.

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Abstract

Hippocampal place cells have spatio-temporal properties: they generally respond to a single spatial position of a small environment; in addition, they also display a temporal property, the theta phase precession, namely that the phase of spiking relative to the theta wave shifts from the late phase to early phase as the animal crosses the place field. Grid cells in layer II of medial entorhinal cortex (MEC) also have spatio-temporal properties similar to hippocampal place cells, except that grid cells respond to multiple spatial locations that form a hexagonal pattern. Other non-grid spatial cells are also abundant in the entorhinal cortex (EC). EC is the upstream that projects strongly to the hippocampus, many EC-hippocampus models have been designed to explain how the spatial property of place cells emerges. However, there is no learning model explaining how the temporal properties of hippocampal place cells emerge from the EC input. A learning model is presented here based on non-negative sparse coding in which we show that the spatial and temporal properties of hippocampal place cells can be simultaneously learnt from EC input: both MEC grid cells and other EC spatial cells contribute to the spatial properties of hippocampal place cells while MEC grid cells contribute to the temporal properties of hippocampal place cells.