For most mammals, chemical communication is an important source of information about others of the same species. Even in humans, the well-documented menstrual synchrony among women living together is evidence for subliminal communication based on odor cues. Numerous less well-documented anecdotes suggest that chemical communication may also carry other information between individuals. In many mammals, the main olfactory system and an accessory system, the vomeronasal organ and its associated central neural pathways, act together and have a large influence on behavior. The presence of functional vomeronasal organs in humans is questionable but the brain structures evolved to process vomeronasal information, the medial and cortico-medial amygdala, are still prominent in the human brain and still receive chemosensory input. This proposal describes experiments to investigate the function of these brain regions. The model system for these studies is the chemical communication that leads to male hamster reproductive and territorial behavior. Activation of the central vomeronasal neural pathway and the regions it connects to, are the most obvious events in the forebrain during mating or stimulation with female chemosignals - as assessed by the expression of the rapidly induced gene c-fos. Chemosensory stimuli from females and territorial chemical-signals from other males strongly activate this pathway in male hamsters, including both the anterior and posterior medial amygdala. Preliminary data suggest that chemosensory stimuli from other species, biologically important but with no """"""""social"""""""" relevance for hamsters strongly activate the first stage of one branch of the pathway (anterior medial amygdala), but that activation is not passed on to the next brain region (posterior medial amygdala). Artificial stimulation of the vomeronasal pathway by electrical stimulation or an excitatory drug also activates anterior but not posterior medial amygdala. We will test the hypothesis that there is a functional filter in the amygdala that selects input information for onward transmission and processing by posterior medial amygdala on the basis of its social relevance. The accessory olfactory bulb, a prior relay in the system, appears differently selectivity for the same stimuli. We will use electrophysiology and c-los gene expression to confirm these selectivities of response and to investigate whether spatial and temporal patterns of activation, or the activation of certain classes of cells, could be the mechanism.

Agency
National Institute of Health (NIH)
Institute
National Institute on Deafness and Other Communication Disorders (NIDCD)
Type
Research Project (R01)
Project #
1R01DC005813-01
Application #
6563104
Study Section
Integrative, Functional and Cognitive Neuroscience 8 (IFCN)
Program Officer
Davis, Barry
Project Start
2002-12-01
Project End
2005-11-30
Budget Start
2002-12-01
Budget End
2003-11-30
Support Year
1
Fiscal Year
2003
Total Cost
$288,918
Indirect Cost
Name
Florida State University
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
790877419
City
Tallahassee
State
FL
Country
United States
Zip Code
32306
Westberry, Jenne M; Meredith, Michael (2016) GABAergic mechanisms contributing to categorical amygdala responses to chemosensory signals. Neuroscience 331:186-96
Blake, C B; Meredith, M (2011) Change in number and activation of androgen receptor-immunoreactive cells in the medial amygdala in response to chemosensory input. Neuroscience 190:228-38
Samuelsen, C L; Meredith, M (2011) Oxytocin antagonist disrupts male mouse medial amygdala response to chemical-communication signals. Neuroscience 180:96-104
Moeller, John F; Meredith, Michael (2010) Differential co-localization with choline acetyltransferase in nervus terminalis suggests functional differences for GnRH isoforms in bonnethead sharks (Sphyrna tiburo). Brain Res 1366:44-53
Blake, Camille Bond; Meredith, Michael (2010) Selective enhancement of main olfactory input to the medial amygdala by GnRH. Brain Res 1317:46-59
Mast, Thomas G; Samuelsen, Chad L (2009) Human pheromone detection by the vomeronasal organ: unnecessary for mate selection? Chem Senses 34:529-31
Samuelsen, Chad L; Meredith, Michael (2009) Categorization of biologically relevant chemical signals in the medial amygdala. Brain Res 1263:33-42
Samuelsen, C L; Meredith, M (2009) The vomeronasal organ is required for the male mouse medial amygdala response to chemical-communication signals, as assessed by immediate early gene expression. Neuroscience 164:1468-76
Nolte, Christopher M; Meredith, Michael (2005) mGluR2 activation of medial amygdala input impairs vomeronasal organ-mediated behavior. Physiol Behav 86:314-23
Meredith, Michael; Westberry, Jenne M (2004) Distinctive responses in the medial amygdala to same-species and different-species pheromones. J Neurosci 24:5719-25