Abstract
Purpose We perceive object movements though various modalities such as vision, audition and somatosensation, An important question is how motion signals from different modalities are integrated. The present study investigated the influence of haptic information provided by hand movements on visual motion perception measuring motion aftereffect (MAE). Methods A visual stimulus was a radial grating, which was rotated either by the observer's hand movement or by the hand movement data recorded in a previous session. In the former condition, the visual motion synchronized with the hand movements while it did not in the latter condition. In the adaptation with hand movements, observers rotated the arm of a haptic device with the right hand for 20 sec, and the signal from the device rotated the radial grating. The rotation of the radial grating was either in the same direction as the hand with the same speed as the hand, the opposite direction with the same speed, or the same direction with a different speed. In the adaptation without the hand movements, the radial grating was rotated using the position signal recorded in the adaptation with the hand movements. After the adaptation, a static radial grating was presented. Observers indicated the time of MAE disappearance by pressing a button. Results and discussion When the visual movements were the same speed and the same direction as the hand movements, MAE duration in the hand movement condition was longer than that in the no hand movement condition. When the visual movements were in the direction opposite to the hand movements, MAE duration in the hand movement condition was shorter than that in the no hand movement condition. Lengthening MAE duration by hand movements decreased with the increase of the difference in speeds between the visual and hand movements. These results suggest that haptic information influences visual motion perception.
This work has been partially supported by a Grant-in-Aid for Scientific Research for Young Scientists (B) (18700253) from the Japanese Ministry of Education, Culture, Sports, Science and Technology to K.M.