Figure 6.

Head direction (HD) cells exhibited postrotational bursting in head-fixed sessions. A, Six example cells, three recorded during head-fixed rotations in the dark (left column), and three recorded in the light (right column). Plots are clipped to the end of the rotation phase (from 5 s before to 15 s after rotations ended), black lines denote the animal’s HD, red markers represent action potentials, black shaded areas show spike count histograms (200-ms bins). Blue triangles denote detected spike bursts (Materials and Methods, Spike bursts), blue text between two triangles gives the duration between these bursts. In the dark, cells fired bursts of spikes after the rotations ended, initial bursts occurred at a frequency close to the rotation frequency, but the time between consecutive bursts increased steadily. In the light this postrotational bursting was absent. See Extended Data Figure 6-1 for further example cells. B, Same as A but for Experiment 2, where rats could actively locomote during rotations. Postrotational bursting was not observed in the light or dark sessions. See Extended Data Figure 6-2 for further example cells. An additional analysis using the Fast Fourier transform method can also be seen in Extended Data Figure 6-3.