MOTION TEMPLATES WITH EYE VELOCITY GAIN FIELDS FOR TRANSFORMATION OF RETINAL TO HEAD CENTRIC FLOW

HEADING perception from the optic flow is more difficult during eye ro tations than when the eye is stationary, because the centre of the ret inal motion identifies the fixation direction rather than the directio n of heading. Eye movement signals helps when motion parallax is absen t. This paper distinguishes two different possibilities for interactio ns between eye movement and visual motion signals to perceive heading with a rotating eye. A pre-motion template transformation changes loca l retinal velocity into head centric velocity. These velocities then f eed head centric motion templates. A postmotion template model combine s oculomotor signals with retinal motion templates to arrive at head c entric flow templates. The latter scheme involves eye velocity gain fi elds similar to the eye position gain fields as found in area 7a. We p ropose that the parietal cortex transforms retinal to head centric dir ection and retinal to head centric flow on the same principle.