Dendritic organization of olfactory inputs to medial amygdala neurons

Abstract

The medial amygdala (MeA) is a central hub in the olfactory neural network. It receives vomeronasal information directly from the accessory olfactory bulb (AOB) and main olfactory information largely via odor-processing regions such as the olfactory cortical amygdala (CoA).Howthese inputs are processed byMeAneurons is poorly understood. Using the GAD67-GFP mouse, we show thatMeA principal neurons receive convergent AOB and CoA inputs. Somatically recorded AOB synaptic inputs had slower kinetics than CoA inputs, suggesting that they are electrotonically more distant. Field potential recording, pharmacological manipulation, and Ca2+ imaging revealed that AOB synapses are confined to distal dendrites and segregated from the proximally located CoA synapses. Moreover, unsynchronized AOB inputs had significantly broader temporal summation that was dependent on the activation of NMDA receptors. These findings show that MeA principal neurons process main and accessory olfactory inputs differentially in distinct dendritic compartments.