Supplementary Figure 1: Nissl-stained sagittal sections for 11 rats with grid cells in MEC layers II–V and 2 rats with head direction cells at the MEC-parasubiculum border (PaS).

Rat identity, brain hemisphere (L = left, R = right), and MEC or MEC-PaS layer are indicated at the top. Black arrowheads indicate the most dorsal and most ventral recording location along the tetrode track.