| Title: | Ultrastructure and synaptic connectivity of main and accessory olfactory bulb efferent projections terminating in the rat anterior piriform cortex and medial amygdala |
| Author(s): | Park SK; Kim JH; Yang ES; Ahn DK; Moon C; Bae YC; |
| Address: | "Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, 188-1, 2-Ga, Samdeok-Dong, Jung-Gu, Daegu, 700-412, Korea" |
| DOI: | 10.1007/s00429-013-0588-5 |
| ISSN/ISBN: | 1863-2661 (Electronic) 1863-2653 (Linking) |
| Abstract: | "Neurons in the main olfactory bulb relay peripheral odorant signals to the anterior piriform cortex (aPir), whereas neurons of the accessory olfactory bulb relay pheromone signals to the medial amygdala (MeA), suggesting that they belong to two functionally distinct systems. To help understand how odorant and pheromone signals are further processed in the brain, we investigated the synaptic connectivity of identified axon terminals of these neurons in layer Ia of the aPir and posterodorsal part of the MeA, using anterograde tracing with horseradish peroxidase, quantitative ultrastructural analysis of serial thin sections, and immunogold staining. All identified boutons contained round vesicles and some also contained many large dense core vesicles. The number of postsynaptic dendrites per labeled bouton was significantly higher in the aPir than in the MeA, suggesting higher synaptic divergence at a single bouton level. While a large fraction of identified boutons (29%) in the aPir contacted 2-4 postsynaptic dendrites, only 7% of the identified boutons in the MeA contacted multiple postsynaptic dendrites. In addition, the majority of the identified boutons in the aPir (95%) contacted dendritic spines, whereas most identified boutons in the MeA (64%) contacted dendritic shafts. Identified boutons and many of the postsynaptic dendrites showed glutamate immunoreactivity. These findings suggest that odorant and pheromone signals are processed differently in the brain centers of the main and accessory olfactory systems" |
| Keywords: | "Amygdala Animals Dendrites/ultrastructure Glutamic Acid/metabolism Horseradish Peroxidase/metabolism Male Microscopy, Immunoelectron Neural Pathways/*physiology Neurons/*ultrastructure Olfactory Bulb Prefrontal Cortex/*cytology Rats Rats, Sprague-Dawley S;" |
| Notes: | "MedlinePark, Sook Kyung Kim, Jong Ho Yang, Eun Sun Ahn, Dong Kuk Moon, Cheil Bae, Yong Chul eng Research Support, Non-U.S. Gov't Germany 2013/06/13 Brain Struct Funct. 2014 Sep; 219(5):1603-13. doi: 10.1007/s00429-013-0588-5. Epub 2013 Jun 12" |
