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.
|Commitee:||Brunkow, Paul, Petruccelli, Emily|
|School:||Southern Illinois University at Edwardsville|
|School Location:||United States -- Illinois|
|Source:||MAI 81/3(E), Masters Abstracts International|
|Subjects:||Genetics, Behavioral Sciences, Biology|
|Keywords:||CNS, Memory, Planarian, Regeneration, Schmidtea mediterranea, Stem cell|
Copyright in each Dissertation and Thesis is retained by the author. All Rights Reserved
The supplemental file or files you are about to download were provided to ProQuest by the author as part of a
dissertation or thesis. The supplemental files are provided "AS IS" without warranty. ProQuest is not responsible for the
content, format or impact on the supplemental file(s) on our system. in some cases, the file type may be unknown or
may be a .exe file. We recommend caution as you open such files.
Copyright of the original materials contained in the supplemental file is retained by the author and your access to the
supplemental files is subject to the ProQuest Terms and Conditions of use.
Depending on the size of the file(s) you are downloading, the system may take some time to download them. Please be