RT Journal Article
SR Electronic
T1 Fine-Scale Plasticity of Microscopic Saccades
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 11665
OP 11672
DO 10.1523/JNEUROSCI.5277-13.2014
VO 34
IS 35
A1 Katharina Havermann
A1 Claudia Cherici
A1 Michele Rucci
A1 Markus Lappe
YR 2014
UL http://www.jneurosci.org/content/34/35/11665.abstract
AB When asked to maintain their gaze steady on a given location, humans continually perform microscopic eye movements, including fast gaze shifts known as microsaccades. It has long been speculated that these movements may contribute to the maintenance of fixation, but evidence has remained contradictory. We used a miniaturized version of saccadic adaptation, an experimental procedure by which motor control of saccades is modified through intrasaccadic displacements of the target. We found that the statistical distribution of microsaccade amplitudes changes after brief exposure to systematic shifts of the fixation point during microsaccade occurrence. Shifts in the same directions as microsaccades produce movements with larger amplitudes, whereas shifts against microsaccade directions result in smaller movements. Our findings show that microsaccades are precisely monitored during fixation and that their motor program is modified if the postsaccadic target position is not at the expected retinal location. These results demonstrate that saccadic adaptation occurs even when the stimulus is already close to the foveal center and precise execution of the movement may not be critical. They support the proposal that adaptation is necessary to maintain a consistent relationship between motor control and its visual consequences and that the representation of space is intrinsically multimodal, even during fixation.