Figure 3.

Responses of an egocentric boundary cell in retrosplenial cortex. A1. Plot in allocentric coordinates shows foraging trajectory in gray. Each time a spike occurs, animal position is plotted as a point with color indicating head direction (color wheel indicates directional coding). A2: Boundaries within 62.5 cm of animal (blue) are plotted in egocentric coordinates relative to animal head direction for a single spike. A3: Boundary positions for three spikes. A4: Example egocentric boundary ratemap constructed after repeating steps A1-A3 for all spikes and normalizing by occupation. Color axis indicates zero (blue) to peak firing (yellow) for this neuron (using MATLAB Parula colormap). B. probability distribution of preferred distance from boundary of all retrosplenial cortex egocentric boundary cells. C. polar histograms and probability density estimates of preferred boundary bearing of all retrosplenial cortex EBCs. Yellow and blue bars correspond to EBCs recorded in the left and right hemisphere, respectively. D. Another example EBC recorded in the retrosplenial cortex. D1, two-dimensional ratemap shows firing rate for animal position in 1.25m² square environment (blue is no firing, yellow is peak firing rate). D2, plot of trajectory in gray with color of dot indicating head direction of animal at time of spike. D3, egocentric plot showing receptive field on the left side of the animal. Adapted from Alexander et al., 2020