Neuroscience 2004 Abstract
| Presentation Number: | 869.4 |
|---|---|
| Abstract Title: | Automatic categorization of conspecific pheromone stimuli by medial amygdala requires vomeronasal input in sexually naive male hamsters but is lost in experienced males. |
| Authors: |
Westberry, J.*1
; Meredith, M.1
1Florida State Univ., Tallahassee, FL |
| Primary Theme and Topics |
Sensory Systems - Chemical senses -- Olfaction: CNS pathways and physiology |
| Session: |
869. Olfaction: Pathways and Physiology of Higher Processing Poster |
| Presentation Time: | Wednesday, October 27, 2004 11:00 AM-12:00 PM |
| Location: | San Diego Convention Center - Hall A-H, Board # W19 |
| Keywords: | Vomeronasal Organ, Pheromone, Hamster, Medial Amygdala |
In male hamsters, medial amygdala responds categorically to chemosensory stimuli, based on their species of origin or social relevance. Using immediate early gene (IEG) expression, we have demonstrated that the anterior medial amygdala (MeA) responds to both conspecific and heterospecific stimuli, but posterior medial amygdala (MeP) responds only to conspecific, socially-relevant stimuli, whether male or female. Heterospecific stimuli also activated the largely GABAergic intercalated nucleus (ICN) of the amygdala, adjacent to MeP, and suppressed GABA-receptor-ir cells in MeP, suggesting inhibition of MeP by ICN. A similar categorization occurs in mice (Samuelsen et al SfN-04). In hamster, it appears to be hard-wired and dependent on VNO input. Lesions of the main olfactory epithelium (OLFX) in sexually-naive males did not change the characteristic patterns of IEG activation in MeA/MeP elicited by conspecific and heterospecific stimuli, while removal of the VNO (VNX) eliminated categorization and most of the response in the MeA and MeP. VNX impairs mating in naive but not in sexually-experienced males, which use main olfactory input to maintain the behavior. However, after experience the categorization of responses in MeA and MeP is lost. Both experienced-intact and experienced-VNX males show activation of MeA and MeP with both conspecific and heterospecific stimuli. Without VNO input, there was no clear correlation of ICN activation with lack of activation of MeP with either class of stimuli. There were no significant differences in attention to the chemosensory stimuli (on swabs) that could account for differences in amygdala IEG expression between groups.
Supported by DC-005813 from NIDCD
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2004 Neuroscience Meeting Planner. San Diego, CA: Society for Neuroscience, 2004. Online.
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