Sensitivity to full-field visual movement compatible with head rotation: variations with eye-in-head position.
Variations in velocity detection thresholds for full-field visual rotation about various axes are compatible with a simple channel-based system for coding the axis and velocity of the rotation (Harris & Lott, 1995). The present paper looks at the frame of reference for this system. The head-centered, craniotopic reference system and the retinal-based, retinotopic reference systems were separated by using eccentric eye positions. We measured the threshold for detecting full-field visual rotation about a selection of axes in the sagittal plane with the eyes held either 22 1/2 degs up, straight ahead or 22 1/2 degs down in the head. The characteristic features of the variation in detection thresholds did not stay stable in craniotopic coordinates but moved with the eyes and were constant in retinotopic coordinates. This suggests that the coding of head rotation by the visual system is in retinotopic coordinates.
Harris
L R
LR
Department of Psychology, York University, Toronto, Canada.
Lott
L A
LA
D000328:Adult; D000704:Analysis of Variance; D005133:Eye Movements / Q000502:physiology*; D006257:Head; D006801:Humans; D009039:Motion Perception / Q000502:physiology*; D009068:Movement / Q000502:physiology*; D012160:Retina / Q000502:physiology; D012399:Rotation; D012684:Sensory Thresholds / Q000502:physiology*; D014794:Visual Fields / Q000502:physiology*