do neck motor commands attenuate VO responses?
We first tested whether neck efference copy signals provide direct inhibitory inputs to VO neurons (mechanism A; Fig. 2) by specifically characterizing their response during large-amplitude (>25°) saccades. Large saccades in monkeys (Bizzi et al., 1971; Vidal et al., 1982; Lestienne et al., 1984) and humans (André-Deshays et al., 1991) are normally accompanied by the production of significant neck torque even if the subject is head-restrained. However, previous studies have not described the responses of VO neurons during large head-restrained saccades. To confirm that large saccades were accompanied by the generation of neck torque and, in turn, to test whether the underlying neck motor command provided direct inhibitory inputs to VO neurons, we measured the neck torque produced by the monkey during large-amplitude saccades for a subset of neurons (n = 12) in three monkeys. In Figure 3, eye and torque trajectories and unit responses of example neuron cr37_3 were aligned on saccade ons
