Fig. 3.

Characteristics of path cells. (A) Each path cell is indicated by a dot positioned to indicate its value of A_dir, the fraction of the environment at which it exhibited directional firing, and D_pref, the proportion of these directional locations that were in the cell's preferred direction (Materials and Methods). Color indicates the brain region where the cell was observed. Black dashed line separates clockwise or counterclockwise path cells (D_pref ≥ 0.95) and complex path cells (D_pref < 0.95). Only path cells from brain regions where significant numbers of path cells were observed are included. (B) Mean value of A_dir for all path cells in each region; error bars denote 95% confidence intervals. (C) Histogram for values of D_pref from path cells in each region. Horizontal axis (D_pref) has the same scale for A and C. (D) Regional distribution of path cells: Bars depict percentage of neurons observed in each brain area that were path cells. Dark shading indicates clockwise or counterclockwise path cells; light shading indicates complex path cells. Region key: A, amygdala; Cx, parietal and temporal cortices; EC, entorhinal cortex; Fr, Frontal cortices; H, hippocampus; PHG, parahippocampal gyrus. Black dashed line and letter x indicate the percent of path cells expected by chance (Type 1 error rate). Asterisks indicate regions in which the number of observed path cells significantly exceeded the Type 1 error rate (one-sided binomial test; black asterisks, P < 0.05; gray asterisk, P = 0.06).