 |
| Research article summary (published 4 May 2009): |
Rod phototransduction determines the trade-off of temporal integration and speed of vision in dark-adapted toads.
Full Abstract
Human vision is approximately 10 times less sensitive than toad vision on a cool night. Here, we investigate (1) how far differences in the capacity for temporal integration underlie such differences in sensitivity and (2) whether the response kinetics of the rod photoreceptors can explain temporal integration at the behavioral level. The toad was studied as a model that allows experimentation at different body temperatures. Sensitivity, integration time, and temporal accuracy of vision were measured psychophysically by recording snapping at worm dummies moving at different velocities. Rod photoresponses were studied by ERG recording across the isolated retina. In both types of experiments, the general timescale of vision was varied by using two temperatures, 15 and 25 degrees C. Behavioral integration times were 4.3 s at 15 degrees C and 0.9 s at 25 degrees C, and rod integration times were 4.2-4.3 s at 15 degrees C and 1.0-1.3 s at 25 degrees C. Maximal behavioral sensitivity was fivefold lower at 25 degrees C than at 15 degrees C, which can be accounted for by inability of the "warm" toads to integrate light over longer times than the rods. However, the long integration time at 15 degrees C, allowing high sensitivity, degraded the accuracy of snapping toward quickly moving worms. We conclude that temporal integration explains a considerable part of all variation in absolute visual sensitivity. The strong correlation between rods and behavior suggests that the integration time of dark-adapted vision is set by rod phototransduction at the input to the visual system. This implies that there is an inexorable trade-off between temporal integration and resolution.
Author information
Author/s: Haldin, Charlotte (C); Nymark, Soile (S); Aho, Ann-Christine (AC); Koskelainen, Ari (A); Donner, Kristian (K);
Affiliation: Department of Biological and Environmental Sciences, University of Helsinki, FI-00014 Helsinki, Finland.
Journal and publication information
Publication Type: In Vitro; Journal Article; Research Support, Non-U.S. Gov't
Journal: The Journal of neuroscience : the official journal of the Society for Neuroscience (J Neurosci), published in United States. (Language: eng)
Reference: 2009-May; vol 29 (issue 18) : pp 5716-25
Dates: Created 2009/05/07; Completed 2009/05/28;
PMID: 19420240, status: MEDLINE (last retrieval date: 5/28/2009, IMS Date: 28 May 2009 00:00:00)
Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.
External Links for this article
(including full text providers, if available):
Click Electronic Full-text Provider Links to see options for finding the electronic full text links to this article. Note there may be a subscription or fee required for access to the full text. See our FAQ for information on finding FREE full text articles.
This article may also be located in paper journal collections available in many libraries. Use the Journal and Publication Information above to find the full article.
MeSH headings (categories)
This article was linked to the MESH Headings shown below.
Related articles
This article has not been indexed for related articles as yet, however you can still use the live related article search links below.
See a large map of 100+ related articles.