Figure 2.

Example responses from SP and DP cells during measurements of 3D heading tuning. A, B, Response PSTHs for example neurons having SP (A) and DP (B) dynamics. Each PSTH shows the mean response to one stimulus direction defined in spherical coordinates by its azimuth (varying along the abscissa) and elevation (varying along the ordinate) angles. Vertical dashed black lines (t = 0.85 s) in panel A indicate the time at which the maximum response across directions occurred (peak time). Vertical dashed red (t = 0.95 s) and green (t = 1.45 s) lines in panel B illustrate the two peak times for the DP cell. PSTHs were computed with sequential 25-ms bins and then smoothed with a 400-ms sliding window. C, Color contour map showing the 3D heading tuning profile (Lambert cylindrical projection) at peak time for the SP cell of panel A. This SP cell was significantly tuned for heading (ANOVA, p = 3.3 × 10⁻⁹), with a preferred direction (computed as the vector sum of response) at azimuth = 11° and elevation = 3°, corresponding to a rightward and slightly downward movement. D, E, Color contour maps showing 3D heading tuning profiles at the two peak times for the DP cell of panel B. The direction tuning at the first peak time had a heading preference at [azimuth, elevation] = [−60°, 36°] (D), whereas the later peak of tuning was centered at [azimuth, elevation] = [112°, −40°] (E). The difference between the two direction preferences for this neuron was 172°.