RT Journal Article
SR Electronic
T1 Blind Saccades: An Asynchrony between Seeing and Looking
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 4317
OP 4321
DO 10.1523/JNEUROSCI.0352-08.2008
VO 28
IS 17
A1 Claudio de'Sperati
A1 Gabriel Baud-Bovy
YR 2008
UL http://www.jneurosci.org/content/28/17/4317.abstract
AB Saccades may not always wait for the completion of the perceptual analysis. By taking advantage of a motion-induced illusion of position and of the spontaneous scatter of saccade latency, we showed that in normal observers, regular saccades (latency, ∼200 ms) were accurately directed to the target, whereas at higher latencies, saccades were increasingly biased by visual motion until they reflected the perceptual illusion. We reconstructed the time course of saccadic direction coding and identified an early phase in which saccades are mostly predictive (latencies less than ∼100 ms), followed by a phase in which saccades are guided by the target position signal (latencies ∼100–250 ms), and a later phase associated with the buildup of mislocalization (∼250–450 ms). This transient dissociation between action and perception indicates that seeing and looking are based on asynchronous processes, possibly because of independent thresholds for saccades and perceptual localization. The metrics of a saccade would then reflect the evolution of cortical visual signals from a predictive state to a perceptual state, passing through an intermediate visuomotor state. If saccades occur during the visuomotor state, they escape the tricks of perception.