Linked Life Data

3134619

Source:http://linkedlifedata.com/resource/pubmed/id/3134619

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6180
pubmed:dateCreated
1988-8-25
pubmed:abstractText
The weakest pulse of light a human can detect sends about 100 photons through the pupil and produces 10-20 rhodopsin isomerizations in a small retinal area. It has been postulated that we cannot see single photons because of a retinal noise arising from randomly occurring thermal isomerizations. Direct recordings have since demonstrated the existence of electrical 'dark' rod events indistinguishable from photoisomerization signals. Their mean rate of occurrence is roughly consistent with the 'dark light' in psychophysical threshold experiments, and their thermal parameters justify an identification with thermal isomerizations. In the retina of amphibians, a small proportion of sensitive ganglion cells have a performance-limiting noise that is low enough to be well accounted for by these events. Here we study the performance of dark-adapted toads and frogs and show that the performance limit of visually guided behaviour is also set by thermal isomerizations. As visual sensitivity limited by thermal events should rise when the temperature falls, poikilothermous vertebrates living at low temperatures should then reach light sensitivities unattainable by mammals and birds with optical factors equal. Comparison of different species at different temperatures shows a correlation between absolute threshold intensities and estimated thermal isomerization rates in the retina.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0028-0836
pubmed:author
pubmed:issnType
Print
pubmed:day
28
pubmed:volume
334
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
348-50
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1988
pubmed:articleTitle
Low retinal noise in animals with low body temperature allows high visual sensitivity.
pubmed:affiliation
Department of Zoology, University of Helsinki, Finland.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't