Dissertation/Thesis Abstract

The Test of Time: Clock Control of Associative Memory in Drosophila melanogaster with Special Inclusion of FlyBuilder: A Teaching Tool and Curriculum for the Practical Use of Drosophila in Genetics
by Flyer-Adams, Johanna G., Ph.D., Brandeis University, 2020, 193; 28088029
Abstract (Summary)

Memory plays an essential role in the survival of all living organisms, and thus understanding the many factors which influence memory is of critical importance. One such factor is that of the circadian clock, an internal biological timekeeper composed of a conserved molecular core clock and, in invertebrates such as Drosophila and mammals alike, a neural core clock circuit in the brain. Collectively, the circadian clock acts to optimize an organism’s biological and behavioral processes—such as memory—by directing their rhythmic cycling with a periodicity set by external cues such as the sun. Circadian effects on human memory have been observed for over 100 years, and particular components of the molecular clock have been implicated in this phenomenon in both mammalian and Drosophila models. However a neural pathway by which the clock regulates memory has yet to be discovered. This dissertation examines a role for the core clock circuit signaling peptide Pigment-dispersing factor (PDF) and its canonical receptor PDFR in regulation of memory in the fruit fly Drosophila melanogaster. It was found that the PDF signaling pathway is required for associative olfactory short- and long-term appetitive memory. Its requirement for appetitive STM is time-of-day independent, though the magnitude of its contribution is not, and evidence of a latent independent oscillator was found in wildtype flies. PDF can regulate locomotor activity and memory independently, and its effects on appetitive STM are achieved by signaling to targets outside of the core clock circuit and the memory-relevant mushroom body. The clock-based PDF signal is required for aversive olfactory STM as well but likely acts through a second unknown PDF receptor to perform this role, demonstrating a valence-specific level of control by the clock over memory. Behavioral and functional imaging screens to identify the neural target of PDF involved in clock-memory regulation were also conducted, producing an acquisition and data analysis pipeline useful in future studies. Lastly, a pedagogical tool was developed to train undergraduate Drosophila researchers in practical application of balancer chromosomes; this was expanded into FlyBuilder, a multimodal three-part curriculum which allows dry-lab hands-on application of Mendelian genetics, and can be integrated into a variety of undergraduate courses.

Indexing (document details)
Advisor: Griffith, Leslie C.
Commitee: Rosbash, Michael, Garrity, Paul A., Kaun, Karla R.
School: Brandeis University
Department: Biology
School Location: United States -- Massachusetts
Source: DAI-A 82/3(E), Dissertation Abstracts International
Subjects: Neurosciences, Science education
Keywords: Circadian, Memory, Mendelian genetics, Peptide
Publication Number: 28088029
ISBN: 9798664799088
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