Figure 10.

Simulated retrosplenial neurons code for conjunctions of place and direction. A, RSC cells in 4 different sheets (for color code, see C, left) cover the entire HD spectrum. B, RSC cells fire only at the location gated by the corresponding place cell (compare with A, blue panel). C, Left, Color code for location in the arena covered by the place fields of different place cells. Right, Egocentric (i.e., attached to the agent), polar coordinate system (dark gray circles with tick marks), superimposed on the place field locations. Colored arrows indicate egocentric landmark bearing compared with veridical HD (black arrowhead at the center of the local coordinate system, parallel across arena). D, A typical connectivity pattern between Vis and RSC, learned during 20 min of exploration. “post,” target neurons in RSC; “pre,” sender neurons in Vis. The weight matrix illustrates the band-like structure of the learned weights, each band corresponding to weights from Vis (pre) to 1 particular RSC sheet (post).