Submitted on October 21, 2003
Accepted on November 4, 2004
The effect of saccadic adaptation on the localization of visual targets
Holger Awater1, David Burr1, Markus Lappe1, M. Concetta Morrone1, and Michael E. Goldberg1*
1 Lehrstuhl fur Allgemeine Zoologie und Neurobiologie, Ruhr Universitat, Bochum, Germany
* To whom correspondence should be addressed. E-mail: meg2008{at}columbia.edu.
Objects flashed briefly around the time of a saccadic eye-movement are grossly mislocalized by human subjects, so they appear to be compressed towards the endpoint of the saccade. In this study we investigate spatial localization during saccadic adaptation, to examine whether the focus of compression tends towards the intended saccadic target, or at the endpoint of the actual (adapted) movement. We report two major results. Firstly, that peri-saccadic focus of the compression does not occur at the site of the initial saccadic target, but tended towards the actual landing site of the saccade. Secondly, and more surprisingly, we observed a large long-term perceptual distortion of space, lasting for hundreds of milliseconds. This distortion did not occur over the whole visual field but was limited to a local region of visual space around the saccade target, suggesting that saccadic adaptation induces a visuo-topic remapping of space. The results imply that the mechanisms controlling saccadic adaptation also affect perception of space and point to a strong perceptual plasticity coordinated with the well-documented plasticity of the motor system.
