Figure 1.

The different effects of rotation are demonstrated in these examples from foragers (A and B) and navigators (C and D). Recordings on the stable arena before and after rotation are in columns 1 and 3, respectively. Recordings during rotation are in column 2. The stationary frame map is above the rotating frame map. Rotation characteristically disrupted firing patterns in the foragers. (A) The cell with a field at 9:00 on the stable arena continued to discharge during the rotation, but the activity was dispersed when viewed from both the stationary (r_sim = 0.12) and rotating (r_sim = −0.09) reference frames. When the rotation was stopped after 10 revolutions, the field was again prominent at 9:00 (r_sim = 0.79). Qualitatively, rotation had the same disruptive effect on the cell in B; however, according to the numerical criterion, the rotating pattern had a marginally significant resemblance to the stable (r_sim = 0.26) but not the stationary pattern (r_sim = 0.17). When the rotation stopped, the pattern returned (r_sim = 0.80). Place cell discharge from the navigators was more often preserved during rotation. (C). In this example, only stationary frame firing was preserved. The stable field at 7:00 was maintained in the stationary frame (r_sim = 0.76), but not in the rotating frame (r_sim = 0.14) and persisted when the rotation stopped (r_sim = 0.70). (D) In this example, the field at 7:30 was stable in both the stationary (r_sim = 0.62) and rotating (r_sim = 0.72) reference frames, as well as after the rotation stopped (r_sim = 0.71). The field in the rotating reference frame has shifted away from the arena wall. The only way that the same spikes could produce stable firing fields in both the stationary and rotating frames is that the cell mostly fired after each full revolution, when the two frames were in register.