Distortion of visual space during pursuit eye movements

We measured perceived positions of Bash stimuli arranged two-dimensionally in the peripheral visual held during pursuit eye movement to examine the in fluence of displacement of the eye position on localization in the peripher al visual field. The horizontal mislocalization of the flash stimulus durin g the horizontal pursuit eye movement was found toward the pursuit directio n. The magnitude of this mislocalization was asymmetrical around the centra l visual held, and the asymmetry depended on the pursuit direction. As the eye position changed, the magnitude of the horizontal mislocalization gradu ally decreased. It was also observed that the vertical mislocalization of t he Bash stimulus was constant regardless of the eye position displacement. These results show that the visual space during the horizontal pursuit eye movement is expanded horizontally and then gradually returns to the normal state. It is suggested that the visual space is dynamically distorted durin g the pursuit eye movement.