Continuous Attractor Network Model for Conjunctive Position-by-Velocity Tuning of Grid Cells
Figure 4
The units develop stable position-by-velocity maps on a two-meter linear track in a simulation of 20 minutes (parameters: ).
(A) Part of the trajectory of the virtual animal. (B) One snapshot of the network activity during the simulation. (C) The velocity of the bumps is linearly related to the velocity of the virtual rat. Every 100 ms, the instantaneous velocities of the bumps and the animal during 1 ms interval is shown by a dot in the plot. The line shows the slope , ref. Eq. 15; (D) The tracking error (the difference between the estimated position and the actual position of the animal) is small compared to the spacing (
cm). (E) Position-by-velocity maps of two conjunctive units (top two rows) and a grid unit (bottom). The coordinate
in the neural space is indicated at the top of each panel. Non-sampled bins are represented by white color.