Neuronal processing delays are compensated in the sensorimotor branch of the visual system.
Moving objects change their position until signals from the photoreceptors arrive in the visual cortex. Nonetheless, motor responses to moving objects are accurate and do not lag behind the real-world position. The questions are how and where neural delays are compensated for. It was suggested that compensation is achieved within the visual system by extrapolating the position of moving objects. A visual illusion supports this idea: when a briefly flashed object is presented in the same position as a moving object, it appears to lag behind. However, moving objects do not appear ahead of their final or reversal points. We investigated a situation where participants localized the final position of a moving stimulus. Visual perception and short-term memory of the final target position were accurate, but reaching movements were directed toward future positions of the target beyond the vanishing point. Our results show that neuronal latencies are not compensated for at early stages of visual processing, but at a late stage when retinotopic information is transformed into egocentric space used for motor responses. The sensorimotor system extrapolates the position of moving targets to allow for precise localization of moving targets despite neuronal latencies.
Kerzel
Dirk
D
Abteilung Allgemeine Psychologie, Justus-Liebig-Universität Giessen, Otto-Behaghel-Strasse 10F, 35394 Giessen, Germany. dirk.kerzel@psychol.uni-giessen.de
Gegenfurtner
Karl R
KR
D006801:Humans; D009039:Motion Perception / Q000502:physiology*; D010775:Photic Stimulation; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology*; D014795:Visual Pathways / Q000502:physiology*