Sharpening the Spatial Tuning Curves of Place Cells in a Feed-Forward Network : The Possible Role of Theta Oscillation-Based Dynamics in the Hippocampus

Properly tuned receptive fields in feed-forward networks depend on topographical input (afferent cells with properly tuned receptive fields connect topographically to their postsynaptic partners with little or no convergence/divergence) or on attractor network dynamics provided by specfic intra-layer lateral connections (recurrent excitation/inhibition). For hippocampal place cells neither might be availabe. We investigated how theta oscillation can transform the dynamics of a simple feed-forward network without topographical input or recurrent connections so that tuning curves of individual cells remain sharp in spite of the considerable convergence/divergence between layers. The mechanism is also shown to be appropriate for describing fine details of place cell firing