• Login
    View Item 
    •   Home
    • UMass Chan Student Research and Publications
    • Morningside Graduate School of Biomedical Sciences
    • Morningside GSBS Dissertations and Theses
    • View Item
    •   Home
    • UMass Chan Student Research and Publications
    • Morningside Graduate School of Biomedical Sciences
    • Morningside GSBS Dissertations and Theses
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Browse

    All of eScholarship@UMassChanCommunitiesPublication DateAuthorsUMass Chan AffiliationsTitlesDocument TypesKeywordsThis CollectionPublication DateAuthorsUMass Chan AffiliationsTitlesDocument TypesKeywordsProfilesView

    My Account

    LoginRegister

    Help

    AboutSubmission GuidelinesData Deposit PolicySearchingUsage StatisticsAccessibilityTerms of UseWebsite Migration FAQ

    Statistics

    Most Popular ItemsStatistics by CountryMost Popular Authors

    Neural Circuit Analyses of the Olfactory System in Drosophila: Input to Output: A Dissertation

    • CSV
    • RefMan
    • EndNote
    • BibTex
    • RefWorks
    Thumbnail
    Name:
    DasGupta_Shamik_reduced.pdf
    Size:
    6.478Mb
    Format:
    PDF
    Download
    Authors
    DasGupta, Shamik
    Faculty Advisor
    Scott Waddell Ph.D.
    Academic Program
    Neuroscience
    UMass Chan Affiliations
    Waddell Lab
    Neurobiology
    Document Type
    Doctoral Dissertation
    Publication Date
    2009-09-17
    Keywords
    olfactory systems
    Drosophila
    neural circuits
    Olfactory Perception
    Olfactory Receptor Neurons
    Discrimination Learning
    Cell Cycle Proteins
    Drosophila Proteins
    Embryo
    Nonmammalian
    Genomic Instability
    Amino Acids, Peptides, and Proteins
    Animal Experimentation and Research
    Embryonic Structures
    Nervous System
    Sense Organs
    Show allShow less
    
    Metadata
    Show full item record
    Abstract
    This thesis focuses on several aspects of olfactory processing in Drosophila. In chapter I and II, I will discuss how odorants are encoded in the brain. In both insects and mammals, olfactory receptor neurons (ORNs) expressing the same odorant receptor gene converge onto the same glomerulus. This topographical organization segregates incoming odor information into combinatorial maps. One prominent theory suggests that insects and mammals discriminate odors based on these distinct combinatorial spatial codes. I tested the combinatorial coding hypothesis by engineering flies that have only one class of functional ORNs and therefore cannot support combinatorial maps. These files can be taught to discriminate between two odorants that activate the single functional class of ORN and identify an odorant across a range of concentrations, demonstrating that a combinatorial code is not required to support learned odor discrimination. In addition, these data suggest that odorant identity can be encoded as temporal patterns of ORN activity. Behaviors are influenced by motivational states of the animal. Chapter III of this thesis focuses on understanding how motivational states control behavior. Appetitive memory in Drosophilaprovides an excellent system for such studies because the motivational state of hunger promotes reliance on learned appetitive cues whereas satiety suppresses it. We found that activation of neuropeptide F (dNPF) neurons in fed flies releases appetitive memory performance from satiety-mediated suppression. Through a GAL4 screen, we identified six dopaminergic neurons that are a substrate for dNPF regulation. In satiated flies, these neurons inhibit mushroom body output, thereby suppressing appetitive memory performance. Hunger promotes dNPF release, which blocks the inhibitory dopaminergic neurons. The motivational drive of hunger thus affects behavior through a hierarchical inhibitory control mechanism: satiety inhibits memory performance through a subset of dopaminergic neurons, and hunger promotes appetitive memory retrieval via dNPF-mediated disinhibition of these neurons. The aforementioned studies utilize sophisticated genetic tools for Drosophila. In chapter IV, I will talk about two new genetic tools. We developed a new technique to restrict gene expression to different subsets of mushroom body neurons with unprecedented precision. We also adapted the light-activated adenylyl cyclase (PAC) from Euglena gracilis as a light-inducable cAMP system for Drosophila. This system can be used to induce cAMP synthesis in targeted neurons in live, behaving preparations.
    DOI
    10.13028/hnnr-hj38
    Permanent Link to this Item
    http://hdl.handle.net/20.500.14038/31766
    Rights
    Copyright is held by the author, with all rights reserved.
    ae974a485f413a2113503eed53cd6c53
    10.13028/hnnr-hj38
    Scopus Count
    Collections
    Neurobiology Student Publications
    Morningside GSBS Dissertations and Theses

    entitlement

     
    DSpace software (copyright © 2002 - 2023)  DuraSpace
    Lamar Soutter Library, UMass Chan Medical School | 55 Lake Avenue North | Worcester, MA 01655 USA
    Quick Guide | escholarship@umassmed.edu
    Works found in eScholarship@UMassChan are protected by copyright unless otherwise indicated.
    Open Repository is a service operated by 
    Atmire NV
     

    Export search results

    The export option will allow you to export the current search results of the entered query to a file. Different formats are available for download. To export the items, click on the button corresponding with the preferred download format.

    By default, clicking on the export buttons will result in a download of the allowed maximum amount of items.

    To select a subset of the search results, click "Selective Export" button and make a selection of the items you want to export. The amount of items that can be exported at once is similarly restricted as the full export.

    After making a selection, click one of the export format buttons. The amount of items that will be exported is indicated in the bubble next to export format.