Student Theses and Dissertations

Author

Jazz Weisman

Date of Award

2023

Document Type

Thesis

Degree Name

Doctor of Philosophy (PhD)

Thesis Advisor

Gaby Maimon

Keywords

Drosophila, virtual reality, insect behavior, navigation, operant conditioning

Abstract

By studying head-fixed or rigidly tethered animals, neuroscientists have been able to make high-resolution neurophysiological and behavioral measurements during naturalistic tasks. Tethered paradigms have a particularly rich history in the study of insect behavior and in this thesis I describe technology that extends by one-hundred fold—from hours to weeks—the timescale over which individual Drosophila can be routinely studied while tethered in place. Specifically, I designed and constructed a new experimental rig that allows a rigidly tethered fly to live for at least two weeks within a virtual reality environment. The fly stands (and is free to walk) on an airsupported ball while viewing a virtual visual environment on a panoramic display. To enable long-term survival, the fly is fed small, nutritive drops, thousands of times over two weeks, at experimentally defined moments. The rigs are compact, such that two dozen or more can fit in a small room, allowing for the study of many flies simultaneously. The rigs are also modular, and easily adapted to new kinds of experiments. I have used them to probe innate behaviors, like sleep and navigation, over long time scales. Moving forward, they may allow scientists to train Drosophila in complex, learned, tasks because they enable the delivery of thousands of rewards over multiple weeks, which can be used as reinforcers in operant or classical conditioning paradigms. Beyond the technology, this thesis also describes a new behavioral tendency in Drosophila. Specifically, I show that when Drosophila are allowed to freely navigate in a simple virtual environment for one to two weeks, they maintain a surprisingly consistent navigational angle as they walk forward. Each fly walks along a unique, preferred, travel direction, for tens to hundreds of meters from a start location. The preferred travel direction can be considered a navigational goal angle because individuals will repeatedly correct for experimentally induced virtual rotations away from this angle. Flies require a visual orienting cue to successfully progress forward along the goal angle—walking in circles without it—and they will return to the same goal angle in the morning after spending a full night (twelve hours) without the cue. These experiments demonstrate that Drosophila can commit to a navigational goal over multiple weeks and they further argue for the existence of navigation-related signals and mechanisms in the fly brain, yet to be discovered, with similarly long persistence times.

Comments

A thesis presented to the faculty of The Rockefeller University in partial fulfillment of the requirements for the degree of Doctor of Philosophy

License and Reuse Information

Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License
This work is licensed under a Creative Commons Attribution-NonCommercial-Share Alike 4.0 International License.

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