Input components and net spatial and directional tuning. a, The dependence of a single (essentially one-dimensional) spatial component of the tuning function of cells in EC on the distance of the rat from the wall to which that component is tied. Two examples are shown, with preferred distances of 0.5 and 1.5, respectively; for each preferred distance, thesolid curve is for the case when the rat is facing the wall, and the dashed curve is for the opposite head direction. Note how the width of the curve changes with preferred distance and actual head direction. b, The net two-dimensional tuning of a sample EC neuron in a rectangular box of dimensions 2 × 1; the preferred location of the cell is (0.5, 0.4); the current heading of the rat at each location is the same as the preferred head direction of the cell. c, This polar plot shows the activity of an EC neuron as a function of the difference between its preferred direction and the actual heading of the rat.d–f, Plots similar to a–c, for the MF inputs to CA3; note that both the spatial and the directional tuning is much sharper here because of the orthogonalization property of the dentate gyrus. For all contour plots in this article, darker shading indicates higher activity, and the contour lines are at 20, 40, 60, and 80% of the maximum activity of the given cell or set of cells. Activities are normalized and the absolute values are omitted in most figures because these could be set arbitrarily in the model by changing parameters essentially unconstrained by experimental data.