Because the hand was travelling in a predominantly rightwards direction at cue onset (with the average speed in that direction 760% greater than upwards, and 490% greater than forwards), we expect the errors to be most prominent in azimuth angle ( Figure 1 B) For stimulation over the cerebellum, the 5.13° (±0.48° SEM) difference in azimuth was highly significant ( Figure 4 A, one-sample t -test, t (32)=10.58, p < 0.0001).
In all five conditions, the changes in elevation angle between stimulated and normal trials were not significantly different from each other [ Figure 4 B, one-way ANOVA ( F (4,78) = 1.11, p = 0.36; post-hoc LSD t -test comparisons showed no significant differences ( p > 0.22), except between cerebellar and parietal stimulation, which approached significance ( p = 0.06, uncorrected)].
However, we found no evidence to support this: there was only one near-significant correlation between change in azimuth angle and change in x error during leftwards movement condition ( p = 0.061, Bonferroni adjusted); this is not the axis in which changes in azimuth angle would be most prominent, given the near-vertical plane of movements ( Figure 1 ).
This corresponds with a small hypermetric overshoot and a small directional error; the increase in overall amplitude of the reach-to-target movement did not reach statistical significance ( p = 0.14).