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In terrestrial vertebrates, the olfactory system is divided into main (MOS) and accessory (AOS) components that process both volatile and nonvolatile cues to generate appropriate behavioral responses. While much is known regarding the molecular diversity of neurons that comprise the MOS, less is known about the AOS. Here, focusing on the vomeronasal organ (VNO), the accessory olfactory bulb (AOB), and the medial amygdala (MeA), we reveal that populations of neurons in the AOS can be molecularly subdivided based on their ongoing or prior expression of the transcription factors Foxp2 or Dbx1, which delineate separate populations of GABAergic output neurons in the MeA. We show that a majority of AOB neurons that project directly to the MeA are of the Foxp2 lineage. Using single‐neuron patch‐clamp electrophysiology, we further reveal that in addition to sex‐specific differences across lineage, the frequency of excitatory input to MeA Dbx1‐ and Foxp2‐lineage neurons differs between sexes. Together, this work uncovers a novel molecular diversity of AOS neurons, and lineage and sex differences in patterns of connectivity. [ABSTRACT FROM AUTHOR]

PACAP exerts neuroprotective effects during development, especially in the cerebellum where PAC1 receptor and ligand are both expressed. However, while previous studies using PACAP injections in postnatal animals defined trophic effects of exogenous peptide, the role of endogenous PACAP remains unexplored. Here, we used PAC1−/− mice to investigate the role of PACAP receptor signaling in postnatal day 7 cerebellum. There was no difference in DNA synthesis in the cerebellar EGL of PAC1−/− compared to wild type animals, assessed using thymidine incorporation and BrdU immunohistochemistry. In contrast, we found that a significant proportion of newly generated neurons were eliminated before they successfully differentiated in the granule cell layer. In aggregate, these results suggest that endogenous PACAP plays an important role in cell survival during cerebellar development, through the activation of the PAC1 receptor. [ABSTRACT FROM AUTHOR]

Cryosectioning, the sectioning of frozen specimens, has been an important histological tool for more than a century and continues to be extensively utilized today. However, the ability to produce high-quality sections is often a difficult process requiring extensive patience and experience. In this chapter, we have detailed an effective method for the embedding, mounting, and sectioning of frozen tissues, as well as have provided suggestions in producing high-quality sections.