Student Theses and Dissertations

Date of Award

2017

Document Type

Thesis

Degree Name

Doctor of Philosophy (PhD)

RU Laboratory

Maimon Laboratory

Abstract

While navigating their environment, many animals keep track of their angular heading over time. However, a neuronal-circuit architecture for computing heading remains unknown in any species. In this thesis, I describe a set of neurons in the Drosophila central complex whose wiring and physiology provide a means to shift an angular heading estimate when the fly turns. I show that these clockwise- and counterclockwise-shifting neurons each exist in two subtypes, with spatiotemporal activity profiles that suggest opposing roles for each subtype at the start and end of a turn. Shifting neurons are required for the heading system to properly track the fly's heading in the dark, and their stimulation induces a shift in the heading signal in the expected direction. I also provide evidence that the angular position of visual landmarks is flexibly associated with the fly’s internal heading estimate as it explores its environment. A specific circuit-level model based on known cell types is proposed to account for this flexible association. The central features of the biological circuits described here are analogous to computational models proposed for headdirection cells in rodents and may inform how neural systems, in general, perform angular calculations.

Comments

A Thesis Presented to the Faculty of The Rockefeller University in Partial Fulfillment of the Requirements for the degree of Doctor of Philosophy

Available for download on Thursday, April 26, 2018

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