Abstract
To examine coordinate frames for FEF pursuit signals, we first compared preferred directions during head-fixed upright position and static 40° roll tilt. Preferred directions of 30 pursuit neurons were shifted minimally during static tilt, indicating that their coordinate frames are not world-centered. In the head-fixed condition, head-centered- and body-centered- coordinates are not dissociated. To dissociate them, the monkeys were allowed to rotate the heads horizontally on the upright stationary body for pursuit of a reward feeder and laser spot. Responding neurons during gaze (eye-in-space)-pursuit were tested for eye-pursuit of the spot while the feeder was stationary and head-pursuit of the feeder while the spot was stationary. Majority (61%) of 99 responsive neurons fired strongly for both eye- and head-pursuit even when gaze was stationary; the modulation during gaze-pursuit was linear sum of modulation during eye- and head-pursuit. Modulation during VOR cancellation induced by passive whole body rotation was not correlated with eye-pursuit modulation. These results suggest that these cells fired for body-centered coordinates. Minority (24%) was modulated during gaze- and eye- pursuit similarly but minimally during head-pursuit when gaze was stationary; modulation during VOR cancellation was correlated well with eye-pursuit modulation, suggesting that these cells fired for head-centered coordinates. Our results suggest that both body-centered and head-centered coordinates are present in FEF for processing eye-, head-, and gaze-pursuit signals. [J Physiol Sci. 2006;56 Suppl:S187]
