Circadian Rhythms
Melibe exhibits circadian rhythms of crawling
In normal light/dark (LD) conditions, Melibe crawl more during the early portion of the dark period (black bars along top).
In constant darkness (DD), Melibe continue with similar rhythms of crawling, although the activity shifts earlier every day because the endogenous clock has a period less than 24 hours.
This work was published in Biological Bulletin in 2014.
Melibe also exhibits circadian rhythms of swimming
Similar patterns of activity in LD and DD occur for swimming, although this form of locomotion is much less prevalent than crawling.
This work was published in Biological Bulletin in 2014.
Methodology for investigating circadian rhythms of Berghia
We are now working to investigate circadian rhythms of locomotion in Berghia stephanieae, a species of nudibranch being developed by Paul Katz and others as a new model for understanding the nervous system.
Animals in individual containers are observed from above via time lapse still images. Daytime lighting is provided by LED lights with wide spectrum wavelengths and images are obtained during darkness via infrared illumination.
All experiments use animals entrained to a 12h:12h light/dark schedule. Some experiments then start with constant darkness for 5-6 days, followed by 3 days of alternating light/dark. Other experiments reverse the order of the light regimes.
Time lapse videos are created and analyzed in Ethovision or DeepLabCut to track distance moved over time.
This methodology has been developed by Connor Dunn, Collin Lambert, and Jordan Vachon, and will be followed up in future experiments.