Supplementary Figure 8: Model performance analysis
From: A faithful internal representation of walking movements in the Drosophila visual system
(a) Predicted velocity tuning maps for different single-component models. (b) Mean cross-correlation coefficients per cell between observed and predicted Vm for different models (black, matched pairs; red, mismatched pairs; see Methods, lines: mean values, **: P<0.001, Z>3.78, N=19 cells, Wilcoxon signed-rank test). Right-most column: cross-correlation coefficients between the observed and the predicted yaw head angle. (c) Performance of the BS and the Va+Vf+BS models in each cell. Indicated are the example cells shown in Fig. 3a, and in (e). (d) Performance of the Va+Vf+BS and the Va+BS models for each cell. Mean (±SD) correlation coefficients between the predicted and observed HS dynamics (see Methods). Red and blue: the difference in the magnitude of correlation coefficients between the two models cannot be explained by the reshuffling procedure (traces were shuffled 20 times by concatenated walking bouts, Wilcoxon’s signed-rank test, P<0.005), whereas the gray pairs can (P >0.02, Wilcoxon‘s signed-rank test). (e) Example of a cell with the lowest three-compartment model performance. Note that the HS cells’ dynamics are still well described by the three-component model. (f) Top, the predicted velocity-tuning map for the example cell in Figure 5c scaled in mm/s units in both axes. θ: the angle between the forward velocity axis and the membrane potential change (ΔVm) gradient (see Methods). Bottom, distribution of θ for each cell; the mean value is indicated in black. The θ value for the observed population velocity map (N=19 cells) is indicated in red. (g) The observed (black) and predicted (magenta) head yaw angles, estimated from the three-component model fitting the head yaw angle instead of the Vm. (h) Power spectrum analysis of the observed, the predicted, and the difference between the two for Vm (left), or yaw head angle (right). Note that the largest difference for the head angle prediction is on the DC component, i.e., the offset of the head position (arrows in (g)).
