Abstract
<title>Abstract</title> <p>Glutamatergic neurons of the amygdala are critical for bridging sensory information with emotional value, and for selecting the appropriate response depending on the context. However, these neurons are highly diverse, and the specific role of each subtype is unknown. Since embryonic origin is crucial for disentangling functional pathways, we studied two subtypes of glutamatergic neurons of the pallial and medial amygdala with different embryonic origin, Emx1-lineage cells derived from the pallium, and Otp cells derived from the telencephalon-opto-hypothalamic domain. To study these cells in adult animals, we used a triple transgenic mice line with specific reporters for Emx1 and Otp cells. In the pallial amygdala, the proportion of Emx1 cells is clearly lower in the anterior radial subunit compared to the rest, while in the medial amygdala the proportion of Otp cells is much higher in the anteroventral subdivision compared to the posterior part. A high proportion of Emx1 and Otp neurons coexpressed COUP-TFII/NR2F2 transcription factor and, less frequently, the calcium binding proteins calretinin or calbindin. Considering the relevance of the amygdala in processing olfactory cues, we studied cFos expression in Emx1 and Otp neurons following exposure to odorants with different biological relevance (water, pentyl acetate or mT/predator). We found differential activation of Otp versus Emx1 cells upon exposure to distinct odorants, with different results depending on the subdivision and the sex. Our results help to understand morphological, functional and sex differences between two glutamatergic neuronal populations of the pallial and medial amygdala with distinct embryonic origin.</p>