Semester

Spring

Date of Graduation

2025

Document Type

Dissertation (Campus Access)

Degree Type

PhD

College

Eberly College of Arts and Sciences

Department

Biology

Committee Chair

Erick Horstick

Committee Co-Chair

Sadie Bergeron

Committee Member

Charles Anderson

Committee Member

Andrew Dacks

Committee Member

Gary Marsat

Abstract

Sensorimotor coordination, the adaptation of motor actions in response to incoming sensory information, is vital for survival of all animals. One important facet of successful sensorimotor coordination is the continued ability to distinguish between particularly between self-made and environmental sources of sensory information. The neural mechanisms underlying sensory source disambiguation are referred to as predictive motor circuits (PMCs). PMCs send motor-related corollary signals from motor pathways to the sensory system in advance of actions that would result in sensory feedback for the animal. One such PMC, originally described in Manduca sexta and found across the insects, are the mesothoracic ascending histamine neurons (MsAHNs), which increase activity prior to and during wing-movement to enhance olfactory acuity. In this dissertation, the homologous MsAHNs are studied in Drosophila melanogaster, taking advantage of available tools for this model organism. The related experiments were used as the basis for development of a novel onboarding course for undergraduate laboratory researchers. The MsAHNs act as a wing-to-motor PMC; however, their functional relationship to downstream motor neurons, specifically, and to behavioral performance, generally, remains unknown. Chapter 1 introduces these concepts in more depth, as well as providing a primer on the need for quality undergraduate researcher education in the laboratory. Chapter 2 examines the inhibitory influence of histamine, which is released by the MsAHNs, on indirect flight motor neuron (IFMN) activity using two-photon microscopy and pharmacological techniques. Here the lack of change in IFMN response following the use of histamine receptor blockers is discussed in terms of what is known about MsAHN homologues. Chapter 3 uses a broad battery of behavioral assays including, odor-guided flight, one focusing on flight quality from takeoff to landing, negative-geotaxis, and a grooming. These assays challenged animals under experimental conditions exploiting multiple genetic tools, to show that the MsAHNs affect flight coordination and negative geotaxis behavior. Chapter 4 illustrates the development and compilation of a Google classroom-based, hybrid asynchronous course. Undergraduate researchers becoming involved in the MsAHN project can use this course to bridge gaps in their knowledge of neuroscience, Drosophila melanogaster biology and husbandry, and genetics. Finally, Chapter 5 compiles the results of this dissertation and broadly discusses the relevance of the work within. In summary, this work establishes the functional role of a PMC in flight and locomotor performance, and a training pipeline that can be expanded to create a new gold-standard for undergraduate training in STEM research that is based on current higher-educational standards.

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