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Categorization of Pheromonal Chemosignals by Medial Amygdala

Title: Categorization of Pheromonal Chemosignals by Medial Amygdala.
Name(s): Westberry, Jenne M., author
Meredith, Michael, professor directing dissertation
Wang, Zuoxin, outside committee member
Freeman, Marc, committee member
Houpt, Thomas, committee member
Keller, Laura, committee member
Department of Biological Science, degree granting department
Florida State University, degree granting institution
Type of Resource: text
Genre: Text
Issuance: monographic
Date Issued: 2003
Publisher: Florida State University
Florida State University
Place of Publication: Tallahassee, Florida
Physical Form: computer
online resource
Extent: 1 online resource
Language(s): English
Abstract/Description: Individual members of many species use chemical signals detected by the vomeronasal system to communicate with other members of the same species. Over the past two decades, research in the chemical senses field has focused on peripheral detection and processing of chemosensory signals by the vomeronasal organ (VNO). Not as much focus has been placed on central processing of these signals once they are detected and communicated to the accessory olfactory bulb (AOB). The studies included in this dissertation were designed to investigate neuronal activation in the medial amygdala, an area of the brain that gets direct input from the accessory olfactory bulb (AOB). Based on immediate early gene (IEG) expression in activated neurons, I found that the medial amygdala responded differently to pheromonal chemosignals from animals that were conspecific (same species) versus heterospecific (different species). The anterior medial amygdala (MeA) responded to both, but posterior medial amygdala (MeP) responded only to conspecific stimuli and was suppressed during responses to heterospecific stimuli or artificial (non-biological) stimuli. These data provide the first report of categorical discrimination of chemosensory signals in the medial amygdala. This categorization was not apparent in the AOB so it appears to reflect a second level of sensory analysis. Additional studies indicated a reciprocal relationship between activation in MeP and in adjacent inhibitory intercalated nucleus (ICN) cells. MeP is the brain area that only responded to conspecific stimuli. Its lack of activation in MeP with heterospecific stimuli is accompanied by selective suppression in MeP neurons expressing GABA-a Receptor and occurs concurrently with significant activation in GABA immunoreactive cells of the adjacent ICN. The ability of neurons in medial amygdala to show a discrimination between conspecific and heterospecific stimuli was not dependent on main olfactory input and MeA is the first place in the vomeronasal pathway where all the information from rostral and caudal accessory olfactory bulb comes together. Immediate early gene expression does not reveal all the neural activity of the brain, but within the limits of this method all indications are that discrimination occurs in the anterior medial amygdala.
Identifier: FSU_migr_etd-1145 (IID)
Submitted Note: A Dissertation Submitted to the Department of Biological Science in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy.
Degree Awarded: Fall Semester, 2003.
Date of Defense: November 3, 2003.
Keywords: Pheromone, Vomeronasal Organ, Amygdala
Bibliography Note: Includes bibliographical references.
Advisory committee: Michael Meredith, Professor Directing Dissertation; Zuoxin Wang, Outside Committee Member; Marc Freeman, Committee Member; Thomas Houpt, Committee Member; Laura Keller, Committee Member.
Subject(s): Biology
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Host Institution: FSU

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Westberry, J. M. (2003). Categorization of Pheromonal Chemosignals by Medial Amygdala. Retrieved from