Research article summary (published 16 Mar 2009):

The main sequence of human optokinetic afternystagmus (OKAN).

Full Abstract

Different types of fast eye movements, including saccades and fast phases of optokinetic nystagmus (OKN) and optokinetic afternystagmus (OKAN), are coded by only partially overlapping neural networks. This is a likely cause for the differences that have been reported for the dynamic parameters of fast eye movements. The dependence of two of these parameters-peak velocity and duration-on saccadic amplitude has been termed "main sequence." The main sequence of OKAN fast phases has not yet been analyzed. These eye movements are unique in that they are generated by purely subcortical control mechanisms and that they occur in complete darkness. In this study, we recorded fast phases of OKAN and OKN as well as visually guided and spontaneous saccades under identical background conditions because background characteristics have been reported to influence the main sequence of saccades. Our data clearly show that fast phases of OKAN and OKN differ with respect to their main sequence. OKAN fast phases were characterized by their lower peak velocities and longer durations compared with those of OKN fast phases. Furthermore we found that the main sequence of spontaneous saccades depends heavily on background characteristics, with saccades in darkness being slower and lasting longer. On the contrary, the main sequence of visually guided saccades depended on background characteristics only very slightly. This implies that the existence of a visual saccade target largely cancels out the effect of background luminance. Our data underline the critical role of environmental conditions (light vs. darkness), behavioral tasks (e.g., spontaneous vs. visually guided), and the underlying neural networks for the exact spatiotemporal characteristics of fast eye movements.

Author information

Author/s: Kaminiarz, Andre (A); Königs, Kerstin (K); Bremmer, Frank (F);

Affiliation: Department of Neurophysics, Philipps-University Marburg, D-35032 Marburg, Germany. andre.kaminiarz(-atsign-)physik.uni-marburg.de

Journal and publication information

Publication Type: Journal Article; Research Support, Non-U.S. Gov't

Journal: Journal of neurophysiology (J Neurophysiol), published in United States. (Language: eng)

Reference: 2009-Jun; vol 101 (issue 6) : pp 2889-97

Dates: Created 2009/05/27; Completed 2009/08/03;

PMID: 19297517, status: MEDLINE (last retrieved date: 8/21/2009)

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

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MeSH headings (categories)

This article was linked to the MeSH Headings (categories) shown below.

Adaptation, Ocular - physiology Adult Female Humans Male Nystagmus, Optokinetic - physiology

Photic Stimulation Reaction Time - physiology Saccades - physiology Time Factors Visual Fields - physiology Young Adult

Note: Bold headings indicate primary MeSH headings or qualifiers.

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