Fit results of Eq. 6 for all 34 cNRTP burst neurons.

*F*is the mean firing rate (in Hz), (*ê*) are the (dimensionless) components of the normalized eye displacement tuning vector,_{x},ê_{y}, ê_{z}*ê*. ς_{i}is the standard deviation of parameter*i*and was obtained by bootstrapping the fit 75 times (see Efron and Tibshirani, 1991).*r*is the correlation coefficient between fit and data, and*N*is the number of saccades, selected on the basis of an optimal amplitude criterion (see Materials and Methods).*R*_{min}and*R*_{max}are the minimum and maximum saccade amplitudes (in deg), selected for each cell. L,R = left/right recording side.F1_152 , Significant torsional component,

*r*≥ 0.7;F1_150 , significant torsional component, 0.6 ≤

*r*≤ 0.7. In 20/34 cells the correlation exceeded 0.7, and in 11/20 the torsional component differed significantly from zero. In 11/34 neurons correlations are higher than 0.8, out of which 5 have a torsional on-direction. For 9/34 cells 0.6 ≤*r*≤ 0.7, and in 5 torsion was unequal to zero. For 5/34 cells*r*< 0.6, and in 2 of these a significant torsion was obtained. Also, from the 10 directional burst neurons, 4 were torsional. Thus, regardless of the criteria applied, in roughly half of the cells (18/34) the obtained torsional component was significant.