Temperature affects all biological processes, from the rate of cellular growth and metabolism to the stability of proteins that make up the machinery of life itself. Thus, all organisms must have the capacity to detect and respond to external temperature. Thermosensation endows animals with the ability to sense and respond to changes in external temperature and is critical for all motile animals to seek thermal conditions that are permissive to their survival, lest they face tissue damage, sterility, and death. While some of the cellular substrates and molecular mechanisms for the detection of external temperature in animals ranging from flies to humans have been described, the organization of the central circuits that process thermosensory information has received comparatively less attention. Equally important for terrestrial animals is humidity, a parameter that co-varies with temperature and directly impacts water homeostasis. Little is currently known about how animals may detect and process changes in external humidity, a sensory modality called hygrosensation. Here, I present my work on the mapping and characterizing central circuits contributing to the processing of thermosensory and hygrosensory information in the brain of the fruit fly Drosophila, a model ideally suited for the dissection of complex circuits and behavior. First, I discuss my contribution to work that led to the first discovery and characterization of second-order thermosensory projection neurons (TPNs), neurons that receive direct synaptic input from thermoreceptors (TRNs) in the fly antenna and target higher brain centers. Next, I describe my work in discovering how hot and dry stimuli are integrated by a specific type of TPN. Finally, I describe my work in characterizing the roles of various TPNs and their downstream targets in thermo- and hygrosensory behavior, ultimately defining a neural circuit involved in the anticipation of and escape from dangerous hygro/thermal conditions. Together, my results help uncover how temperature and humidity changes are processed within multiple layers of this anticipation/escape circuit and demonstrate how this information is utilized to direct adaptive behavior.

Creator

• Jouandet, Genevieve

DOI

• https://doi.org/10.21985/n2-xr7v-1p47

Subject

• Neurosciences

Language

• en

Alternate Identifier

• http://dissertations.umi.com/northwestern:16434
• etdadmin_upload_965903

Keyword

• behavior
• thermosensory
• drosophila
• neural circuit

Date created

• 2023-01-01

Resource type

• Dissertation

Rights statement

• In Copyright