Dissertation/Thesis Abstract

The Optimization and Application of Behavioral Analysis on the Planarian Flatworm Schmidtea mediterranea
by Haines, Jessica N., M.S., Southern Illinois University at Edwardsville, 2019, 70; 22592078
Abstract (Summary)

The planarian flatworm, Schmidtea mediterranea, is a structurally simple model organism; their central nervous system (CNS) comprises of a bi-lobed cephalic ganglia and two ventral nerve cords. Despite their CNS being relatively primitive, planarians are molecularly complex and possess similarities to higher organisms. Planarians can sense a variety of external stimuli, such as tactile information, and direct an appropriate behavioral response to environmental factors. Planarians are capable of being habituated to an environment through repeated exposure. The overall objective of our experiment was to design a behavioral analysis enabling us to identify planarian genes affecting memory. Control planarians were habituated to a rough or smooth surface-type for a total of three weeks while being fed dsRNA expressing GFP, a gene that is absent in the planarian genome. After the sixth RNAi feeding, worms were starved for four or seven days prior to behavioral analysis. We assayed planarian memory through videos taken in infrared light on a rough surface-type testing arena. The overarching idea behind our behavioral analysis is that planarians previously habituated to a rough surface-type will more readily ignore this familiar stimulus, prioritizing food over tactile information, while worms that had been habituated to a smooth surface-type are unfamiliar with this surface and will hesitate before engaging in food-seeking behavior. Another innate behavior planarians have is often referred to as the edge-seeking behavior. So, we designed one of their behavioral assays to assess the worms’ memory based on the number of times worms left and returned to the edge of the testing arena. We hypothesized rough surface-type habituated planarians would leave the edge more readily than smooth surface-type habituated worms resulting in the rough group having a low number for times leaving and localizing to the edge. We also analyzed planarian memory based on the amount of time they spent inside rather than outside of the chemoattractant zone and the longest consecutive duration of time spent in the chemoattractant zone. We hypothesized that planarians familiar with a rough surface would spend more time in the chemoattractant zone than worms unfamiliar with a rough surface. By designing and optimizing a behavioral assay to explore the molecular basis of memory in planarians, we lay the foundation to further investigate roles of genes involved in the memory of higher organisms.

Indexing (document details)
Advisor: Hubert, Amy
Commitee: Brunkow, Paul, Petruccelli, Emily
School: Southern Illinois University at Edwardsville
Department: Biological Sciences
School Location: United States -- Illinois
Source: MAI 81/3(E), Masters Abstracts International
Source Type: DISSERTATION
Subjects: Genetics, Behavioral Sciences, Biology
Keywords: CNS, Memory, Planarian, Regeneration, Schmidtea mediterranea, Stem cell
Publication Number: 22592078
ISBN: 9781088374399
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