Document Detail


Analysis of saccadic short-term plasticity in three dimensions.
MedLine Citation:
PMID:  8560809     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The capacity for short-term adaptation is a well-established property of the horizontal (H) and vertical (V) components of saccades. It allows these directional components, which clearly serve the goal of foveation, to maintain their precision even under changing circumstances. Torsional (T) saccade components, on the other hand, which deal with the orientation of the target on the fovea, have hardly been investigated in adaptation experiments. They appear to be severely restricted by Listing's law during fixations and saccades. The main purpose of Listing's law is far from obvious but could be visual or oculomotor. Better knowledge of the adaptive capacity of the saccadic system in the torsional direction could throw new light on the functional significance of this interesting neural strategy. To study short-term plasticity in the torsional components of saccades, binocular 3D-eye positions were measured, using magnetic search coils. Five normal human subjects were instructed to make uni-directional refixation saccades, while they viewed a large visual scene. To induce a change in the torsional component, the complete stimulus was rapidly rotated during these saccades. We thoroughly investigated the torsional responses of the saccadic system, to see if any short-term adaptive response in torsional direction was induced, in which case the notion of a visual purpose for Listing's law would be strengthened. In none of our experiments, however, did we find any clear adaptive response in torsional direction. To further investigate the reliability of this result and to ascertain that our experimental conditions allowed classical gain adaptation, we also did experiments designed to achieve a combination of torsional adaptation and classic gain shortening in one of the directional components. While gain adaptation was very obvious, none of the experiments provided evidence for a short-term effect in torsion. We conclude that our experiments do not support a purely visual basis for Listing's law.
Authors:
B J Melis; J A van Gisbergen
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Vision research     Volume:  35     ISSN:  0042-6989     ISO Abbreviation:  Vision Res.     Publication Date:  1995 Dec 
Date Detail:
Created Date:  1996-02-26     Completed Date:  1996-02-26     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0417402     Medline TA:  Vision Res     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  3423-37     Citation Subset:  IM; S    
Affiliation:
Department of Medical Physics and Biophysics, University of Nijmegen, The Netherlands.
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MeSH Terms
Descriptor/Qualifier:
Adaptation, Physiological
Adult
Depth Perception / physiology*
Female
Fixation, Ocular
Humans
Male
Rotation
Saccades / physiology*
Time Factors

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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