This study is about the development biology i.e. piriform cortex (PC) is a major cortical processing center for the sense of smell that receives direct inputs from the olfactory bulb. In mice, the PC consists of three neuronal layers, which are populated by cells with distinct developmental origins. One origin of PC neurons is the pool of Dbx1-expressing neural progenitors located in the ventral pallium at the pallial-subpallial boundary. Since the precise mechanisms of PC neuron development are largely unknown, we sought to define the distribution, timing of neurogenesis, morphology and projection patterns of PC neurons from the Dbx1 lineage. We found that Dbx1-lineage neurons are preferentially distributed in layer 2 and enriched in the ventral portion of the PC. Further, Dbx1 neurons are early-born neurons and contribute to most neuronal subtypes in the PC.
Fig: Dbx1 is upregulated in Lhx2 conditional knockout cortices. (a) According to qPCR, the expression levels of Lhx2 and Pax6 are significantly downregulated in the cKO (Lhx2f/f; Emx1Cre) cortex when compared with WT (Lhx2fl/+) at E13.5, while the levels of Dbx1 and Rln are significantly upregulated in cKO mice (n = 3–5; Lhx2, P < 0.001; Pax6, P = 0.0054; Dbx1, P = 0.0085; Rln, P = 0.0412). (b) LacZ staining on coronal sections of Dbx1LacZ cortices of WT (top) and cKO (bottom) embryos at E13.5. From anterior (A) to posterior (P), LacZ+ cells (blue) are specifically located in the pallial–subpallial boundary (PSB, arrowheads) in WT. An increased number of LacZ+ cells (indicated by unfilled arrowheads) was observed in the neocortex (NC) of the cKO. Scale bar, 200 µm. GE, ganglionic eminence; Th, thalamus.
Our data also revealed an enrichment of Dbx1-lineage neurons in the ventral anterior PC that project to the orbitofrontal cortex. These findings suggest a specific association between the developmental origin of PC neurons and their neuronal properties.
Shabangu, T., Chen, HL., Zhuang, Zh. et al. Specific contribution of neurons from the Dbx1 lineage to the piriform cortex. Sci Rep 11,8349 (2021). https://doi.org/10.1038/s41598-021-86512-8