Head Direction Cells Are Present before Eye Opening
(A) Nissl-stained sagittal brain sections with representative recording locations in presubiculum (PrS) and parasubiculum (PaS). See also Figure S1 for recording locations in the remaining animals.
(B) Polar plots showing distribution of firing rate for eight head direction cells recorded before eye opening. Rat number (five digits), postnatal day, and peak firing rate are indicated. All head directions were covered during all recording trials. The low peak rates are representative for the parahippocampal area in this age group [8–10].