Document Detail


Velocity response curves support the role of continuous entrainment in circadian clocks.
MedLine Citation:
PMID:  20348465     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Circadian clocks drive endogenous oscillations in organisms across the tree of life. The Earth's daily light/dark cycle entrains these clocks to the environment. Two major theories of light entrainment have been presented in the literature. The discrete theory emphasizes the instantaneous phase-shifting behavior of short pulses of light, and the continuous theory emphasizes changes to the period of oscillations in constant-light conditions. Historically, the primary tool for predicting and understanding discrete entrainment has been the PRC, which measures discrete adjustments to the clock's phase. The authors present a unified theory, which relies on a velocity response curve (VRC), similar in shape to a PRC, but that describes continuous adjustments to the clock's speed. The VRC explains data from both discrete and continuous light experiments and is therefore an invaluable tool to understand entrainment. The authors relate VRC features to specific entrainment behaviors, such as seasonal adjustments to the phase of entrainment. Furthermore, they estimate a VRC from PRC data and successfully reproduce additional PRC data. Finally, they entrain a VRC-based model to natural light/dark cycles, demonstrating the unified theory's ability to predict clock behavior in the face of a fluctuating signal. The results indicate that a VRC-based model not only provides a comprehensive understanding of entrainment but also has excellent predictive capabilities.
Authors:
Stephanie R Taylor; Alexis B Webb; Katherine S Smith; Linda R Petzold; Francis J Doyle
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  Journal of biological rhythms     Volume:  25     ISSN:  1552-4531     ISO Abbreviation:  J. Biol. Rhythms     Publication Date:  2010 Apr 
Date Detail:
Created Date:  2010-03-29     Completed Date:  2010-06-21     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8700115     Medline TA:  J Biol Rhythms     Country:  United States    
Other Details:
Languages:  eng     Pagination:  138-49     Citation Subset:  IM    
Affiliation:
Department of Computer Science, Colby College, Waterville, ME, USA.
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MeSH Terms
Descriptor/Qualifier:
Algorithms
Animals
Biological Clocks / physiology*
Circadian Rhythm / physiology*
Cricetinae
Light
Mesocricetus
Mice
Models, Theoretical
Oscillometry / methods
Photic Stimulation
Photoperiod
Seasons
Sunlight
Grant Support
ID/Acronym/Agency:
EB007511/EB/NIBIB NIH HHS; GM078993/GM/NIGMS NIH HHS

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


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