Figure 2.

The visual input for the agent model in circular (A) and rectangular (B) arenas. The agent rotates toward and subsequently translates to randomly chosen targets (white dot, thick black line indicates the agent's orientation). The starting location is shown above and a later snapshot below. The visual receptive fields of the visual neurons are shown as radial lines emanating from the agent (resolution 1° in simulations, here shown with 5° resolution for clarity). A Gaussian activity profile is calculated around the midpoint of the part of the visual field covered by the cue card, with a width determined by the number of receptive fields covered by the cue. The circular arena has diameter of 1 m, the rectangular arena has an area of 0.5 × 1.5 m. C, A trajectory sample in the circular arena (for simulations using a rat's trajectory, see also Fig. 8). D, E, Representative raster plots of the Vis population for the circular (D) and rectangular (E) arenas. The activity in the Vis population continues to change after the turn (i.e., during pure translation) because the apparent position of the cue in the visual field is affected by the straight line motion of the agent (parallax).