------- Forwarded message -------
From: "ScienceDirect Publication: Vision Research" <>
To:
Cc:
Subject: Secondary (micro-)saccades: The influence of primary saccade end point and target eccentricity on the process of postsaccadic fixation
Date: Fri, 23 Sep 2011 03:26:04 +0200
Publication year: 2011
Source: Vision Research, Available online 16 September 2011
Sven Ohl, Stephan A. Brandt, Reinhold Kliegl
We examine how the size of saccadic under-/over-shoot and target eccentricity influence the latency, amplitude and orientation of secondary (micro-)saccades. In our experiment, a target appeared at an eccentricity of either 6° or 14° of visual angle. Subjects were instructed to direct their gaze as quickly as possible to the target and hold fixation at the new location until the end of the trial. Typically, increasing saccadic error is associated with faster and larger secondary saccades. We show that secondary saccades at distant in contrast to close targets have in a specific error range a shorter latency, larger amplitude, and follow more often the direction of the primary saccade. Finally, we demonstrate that an undershooting primary saccade is followed almost exclusively by secondary saccades into the same direction while overshooting primary saccades are followed by secondary saccades into both directions. This supports the notion that under- and over-shooting imply different consequences for postsaccadic oculomotor processing. Results are discussed using a model, introduced by, to account for the generation of microsaccades. We argue that the dynamic interplay of target eccentricity and the magnitude of the saccadic under-/over-shoot can be explained by a different strength of activation in the two hemispheres of the saccadic motor map in this model.
Source: Vision Research, Available online 16 September 2011
Sven Ohl, Stephan A. Brandt, Reinhold Kliegl
We examine how the size of saccadic under-/over-shoot and target eccentricity influence the latency, amplitude and orientation of secondary (micro-)saccades. In our experiment, a target appeared at an eccentricity of either 6° or 14° of visual angle. Subjects were instructed to direct their gaze as quickly as possible to the target and hold fixation at the new location until the end of the trial. Typically, increasing saccadic error is associated with faster and larger secondary saccades. We show that secondary saccades at distant in contrast to close targets have in a specific error range a shorter latency, larger amplitude, and follow more often the direction of the primary saccade. Finally, we demonstrate that an undershooting primary saccade is followed almost exclusively by secondary saccades into the same direction while overshooting primary saccades are followed by secondary saccades into both directions. This supports the notion that under- and over-shooting imply different consequences for postsaccadic oculomotor processing. Results are discussed using a model, introduced by, to account for the generation of microsaccades. We argue that the dynamic interplay of target eccentricity and the magnitude of the saccadic under-/over-shoot can be explained by a different strength of activation in the two hemispheres of the saccadic motor map in this model.
Highlights
► Secondary saccade motor programs depend on saccadic error and eccentricity. ► Minimum amplitude and maximum latency are shifted to a small overshoot. ► Saccadic over- and under-shoot differ in their influence on secondary saccades.--
Suggested reading by Kathleen
Geen opmerkingen:
Een reactie posten