Figure 7.

Predicted firing rates in force field based upon the cosine model. A, Polar plots of single neurons' prelearning firing rates (green) and predicted force-field firing rates (red/blue) for FFv counter-field (A₁), FFv with-field (A₂), and FFnv counter-field (A₃). Observed force-field firing rate at the LD (90° in all cases) is also shown (orange). Note that the PDs of the predicted rates (red/blue arrows) are significantly shifted from the PD in prelearning (green arrows) in the direction of the force field (orange arrow). That is, PD shifts clockwise for clockwise force field (A₁ and A₂) and counterclockwise for counterclockwise force field (A₃). B, Left, A single cell's average firing rates in baseline (green) versus force field (orange) learned in all eight directions. Reproduced from Gandolfo et al. (2000), their Fig. 3b. (Copyright © 2000 National Academy of Sciences, U.S.A.). Right, Modulation index calculated for each direction show a good cosine fit (R² = 0.85), consistent with our model predictions.