FIGURE 4.

Construction of 2D place fields. (A) All flights from one experimental session of Bat 2. Flight paths are shown in gray, locations of spike events from a single hippocampal neuron are shown with red circles. Note colors indicating X, Y, and Z axes (green, red, and brown, respectively). (B) Top, heat map of spike rate at different XY locations in the experiment session shown in (A). Maximum spike rate (warmer colors = higher spike rates) is identified at the top right of each panel, green and red highlights on X and Y axes indicate orientation of this panel with respect to (A). Bottom, heat map of spike rate at different XZ locations for the experimental session shown in (A). Colors as in previous panels (note brown color highlighting z-axis). (C) All flights from one experimental session of Bat 3. For this bat, its flight paths were restricted to a narrow corridor (6 m × 2 m × 3 m) by netting (shown as gray shading). Other colors as in (A). (D) Top, heat map of spike rate at different XY locations in the experiment session shown in (C). Bottom, heat map of spike rate at different XZ locations for the experimental session shown in (C).