ILAR Sign up for PNAS Online eTocs
Link: Info for AuthorsLink: Editorial BoardLink: AboutLink: SubscribeLink: AdvertiseLink: ContactLink: Sitemap Link: PNAS Home
Proceedings of the National Academy of Sciences
Link: Current Issue "" Link: Archives "" Link: Online Submission ""  Link: Advanced Search

Published online on November 10, 2003, 10.1073/pnas.2336172100
PNAS | November 25, 2003 | vol. 100 | no. 24 | 14415-14420


This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a colleague
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My File Cabinet
Right arrow Download to citation manager
Right arrow Request Copyright Permission
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via ISI Web of Science (12)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Fernandez, R. I.
Right arrow Articles by Eskin, A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Fernandez, R. I.
Right arrow Articles by Eskin, A.
Social Bookmarking
Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg  
What's this?

 Previous Article  | Table of Contents |  Next Article 

Neuroscience
Circadian modulation of long-term sensitization in Aplysia

Raymond I. Fernandez *, Lisa C. Lyons *, Jonathan Levenson {dagger}, Omar Khabour, and Arnold Eskin {ddagger}

Department of Biology and Biochemistry, University of Houston, Houston, TX 77204-5001

Communicated by Joseph S. Takahashi, Northwestern University, Evanston, IL, September 25, 2003 (received for review May 25, 2003)

As the mechanisms for learning and memory are elucidated, modulation of learning and memory becomes a central issue. We studied the modulation of learning and memory by investigating the circadian regulation of short- and long-term sensitization of the siphon withdrawal reflex in Aplysia. We found that Aplysia exhibited diurnal and circadian rhythms of long-term sensitization (LTS) with significantly greater LTS occurring when animals were trained and tested during the day relative to those trained and tested at night. In contrast to the modulation of LTS, short-term sensitization was not regulated by the circadian clock. Time of training rather than time of testing determined the circadian rhythm of LTS. Animals trained during the subjective day demonstrated LTS when tested during either the day or the night. Conversely, when animals were trained during the night, LTS was not observed when animals were tested either at night or during the day. Thus, the circadian rhythm of LTS is a rhythm in learning rather than a rhythm in recall. The threshold required to elicit siphon withdrawal and the duration of siphon withdrawal were not regulated by the circadian clock. These results indicate that the circadian oscillator exerts strong modulatory influences on one form of long-term memory in Aplysia.

Abbreviations: 5-HT, serotonin; DD, constant darkness; CT, circadian time; LD, light–dark; LTS, long-term sensitization; STS, short-term sensitization; ZT, zeitgeber time.

* R.I.F. and L.C.L. contributed equally to this work.

{dagger} Present address: Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030.

{ddagger} To whom correspondence should be addressed at: Department of Biology and Biochemistry, University of Houston, 369 Science and Research II, Houston, TX 77204-5001. E-mail: eskin{at}uh.edu.


Add to CiteULike CiteULike   Add to Complore Complore   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg    What's this?


This article has been cited by other articles in HighWire Press-hosted journals:


Home page
 Proc. Natl. Acad. Sci. USAHome page
S. Decker, S. McConnaughey, and T. L. Page
Circadian regulation of insect olfactory learning
PNAS, October 2, 2007; 104(40): 15905 - 15910.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurosci.Home page
L. C. Lyons, M. S. Collado, O. Khabour, C. L. Green, and A. Eskin
The circadian clock modulates core steps in long-term memory formation in aplysia.
J. Neurosci., August 23, 2006; 26(34): 8662 - 8671.
[Abstract] [Full Text] [PDF]

Home page
 J Biol RhythmsHome page
L. C. Lyons, O. Rawashdeh, and A. Eskin
Non-ocular circadian oscillators and photoreceptors modulate long term memory formation in aplysia.
J Biol Rhythms, August 1, 2006; 21(4): 245 - 255.
[Abstract] [PDF]

Home page
 J Biol RhythmsHome page
J. H. Houl, W. Yu, S. M. Dudek, and P. E. Hardin
Drosophila CLOCK Is Constitutively Expressed in Circadian Oscillator and Non-Oscillator Cells.
J Biol Rhythms, April 1, 2006; 21(2): 93 - 103.
[Abstract] [PDF]

Home page
 Proc. Natl. Acad. Sci. USAHome page
L. C. Lyons, O. Rawashdeh, A. Katzoff, A. J. Susswein, and A. Eskin
Circadian modulation of complex learning in diurnal and nocturnal Aplysia
PNAS, August 30, 2005; 102(35): 12589 - 12594.
[Abstract] [Full Text] [PDF]

Home page
 J Biol RhythmsHome page
D. Chaudhury, L. M. Wang, and C. S. Colwell
Circadian Regulation of Hippocampal Long-Term Potentiation
J Biol Rhythms, June 1, 2005; 20(3): 225 - 236.
[Abstract] [PDF]

Home page
 J. Neurosci.Home page
O. Khabour, J. Levenson, L. C. Lyons, L. S. Kategaya, J. Chin, J. H. Byrne, and A. Eskin
Coregulation of Glutamate Uptake and Long-Term Sensitization in Aplysia
J. Neurosci., October 6, 2004; 24(40): 8829 - 8837.
[Abstract] [Full Text] [PDF]