Figure 6. Combined condition responses are well approximated by linear weighted summation.

(A) Predicted responses from weighted linear summation are strongly correlated with measured responses under the combined condition (R=0.99, p≪0.001). Each symbol represents the response of one neuron at one heading angle (after spontaneous activity is subtracted). Cyan, red and black symbols are used for congruent (n=36), opposite (n=5) and intermediate (n=15) neurons, respectively. (B) Distribution of correlation coefficients from the linear regression fits. Three cases with negative (but not significant) R² values are not shown. (C) Visual and vestibular weights derived from the best fit of the linear weighted sum model for each neuron with significant R² values (black bars in B). Arrowheads illustrate mean values. Solid lines show Speakman rank correlation. Circles, monkey U; triangles, monkey C.