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Quickly tapping targets that are flashed during smooth pursuit reveals perceptual mislocalisations
Gerben Rotman1, Eli Brenner, Jeroen B J Smeets
1Department of Neuroscience, Erasmus MC, PO Box 1738, 3000 DR Rotterdam, The Netherlands. G.Rotman@erasmusmc.nl
Experimental Brain Research
|February 18, 2004
Summary
During pursuit eye movements, visually perceived targets are often mislocalized. However, this study shows fast hand movements also exhibit this pursuit-induced mislocalization, challenging previous findings.
Area of Science:
- Neuroscience
- Human Perception
- Motor Control
Background:
- Studies show that during pursuit eye movements, people misperceive the location of flashed targets, shifting them in the direction of movement.
- Hansen (1979) reported accurate target hitting with rapid motor responses during pursuit, suggesting a potential difference in sensory information used for perception versus action.
Purpose of the Study:
- To investigate if the sensory information guiding perceptual judgments differs fundamentally from that used for rapid motor responses to visual targets during pursuit.
- To re-examine Hansen's (1979) findings regarding accurate motor responses to flashed targets during pursuit eye movements.
Main Methods:
- Subjects performed rapid index finger tapping tasks on targets flashed during ongoing pursuit eye movements.
- The accuracy of the tapping responses was analyzed in relation to the perceived and actual target positions.
Main Results:
- Subjects systematically tapped ahead of the actual flashed target position, consistent with known perceptual mislocalizations during pursuit.
- This finding contradicts Hansen's (1979) observation of accurate motor responses, indicating that rapid motor actions are not immune to pursuit-induced spatial errors.
Conclusions:
- The lack of systematic errors observed by Hansen (1979) is not a general characteristic of fast motor responses during pursuit.
- Both perceptual judgments and rapid motor actions, like tapping, are subject to similar spatial mislocalizations when targets are presented during pursuit eye movements.