Figure 5.

Population analysis of cosine-tuned theta cells. Cells from rats AT1 and AT2 were recorded in anterior thalamus; for rats MH4–MH6, filled symbols indicate medial septum cells, and open symbols indicate hippocampal cells. A, Circular distribution of preferred movement direction estimates, θ̄, for each theta cell (n = 19) during the first session in which it was recorded with the cue card in the standard position. B, Scatter plot shows estimated base frequency (F̄, x-axis) versus predicted grid spacing (Λ̄, y-axis) for all sessions (n = 31). Dashed lines connect each pair of symbols plotting two different recordings of the same cell, to show within-cell variability of F̄ and Λ̄ across sessions. C, Population averaged DBFT curve (19 theta cells recorded during 31 sessions from 5 rats) is well fit by a cosine function (gray line). D, Population-averaged running speed slopes for movement in the preferred (pref), antipreferred (anti), and orthogonal (ortho) directions of each theta cell (directional ranges indicated by shaded regions in C). Error bars indicate SEM.