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ORCID

https://orcid.org/0000-0002-9202-7010

Access Type

Open Access Thesis

Document Type

thesis

Degree Program

Neuroscience & Behavior

Year Degree Awarded

2021

Month Degree Awarded

September

Abstract

Developing robust behavioral assays to study olfactory-driven behaviors allows for greater insight into the neural mechanisms behind them. Oftentimes, olfactory behavioral assays require a two-choice design, consistent variables, and controlled stimulus application. This can be challenging when working with marine dwelling organisms such as nudibranchs. Extensive work shows the importance of olfaction in both pre-metamorphic larval development and adult stage nudibranchs (Gastropoda, Mollusca). However, there is little research investigating how olfaction plays a role in rapidly developing, post-metamorphic juvenile nudibranchs such as Berghia stephanieae. To study olfactory-associated behaviors in juvenile Berghia, a novel behavioral microfluidic chip was designed which met the requirements for a reliable olfaction assay. Baseline motor behaviors such as general locomotion, turns, and contractions were observed. Despite individuals being raised in the same cohort, animal-to-animal variability was found in relation to their baseline behaviors. Xylene cyanol, a commonly used dye in microfluidics, was found to be aversive at a range of concentrations (0.075% - 0.025%) causing the animal to tightly contract and turn away from the stimulus. Juveniles showed no significant behavioral response to a 0.00125% dilution which was necessary to confirm a constant flow in the microfluidic chip. Juveniles showed a strong preference towards fluid that had been conditioned with their preferred food source odor, the sea anemone Exaiptasia diaphana. This was judged to be an innate preference because it occurred upon the first exposure of these animals to the odor. Serial dilution of Exaiptasia conditioned seawater (ECS) uncovered a threshold for behavioral preference of 60%. In summary, the development of this behavioral provides an opportunity to present controlled olfactory stimuli while observing the juvenile’s behaviors. This will allow future experiments to examine the neural mechanisms behind both aversive and attractive stimuli and provides a method for testing olfactory learning and memory in this species.

DOI

https://doi.org/10.7275/24376382.0

First Advisor

Paul S. Katz

Second Advisor

Rolf O. Karlstrom

Third Advisor

David Moorman

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