Development of the mouse anterior amygdalar radial unit marked by Lhx9-expression

Abstract

The amygdala in mammals plays a key role in emotional processing and learning, being subdivided in pallial and subpallial derivatives. Recently, the cortical ring model and the pallial amygdalar radial model (Puelles et al. 2019; Garcia-Calero et al. 2020) described the pallial amygdala as an histogenetic field external to the allocortical ring, and subdivided it in five major radial domains called lateral, basal, anterior, posterior and retroendopiriform units. The anterior radial unit, whose cells typically express the Lhx9 gene (see molecular profile in Garcia-Calero et al. 2020), is located next to the pallial/subpallial boundary. This radial domain shows massive radial translocation and accumulation of its derivatives into its intermediate and superficial strata, with only a glial palisade representing its final periventricular domain. To better understand the development of this singular radial domain, not described previously, we followed the expression of Lhx9 during mouse amygdalar development in the context of the postulated radial subdivisions of the pallial amygdala and other telencephalic developmental features.

Sim1-expressing cells illuminate the origin and course of migration of the nucleus of the lateral olfactory tract in the mouse amygdala

“…This new, much more complex amygdalar model now explains easily the previously contradictory data of Gorski et al (2002), Puelles (2014) and Puelles et al (2016c). Garcia-Calero andPuelles (2021) reexamined and reinterpreted the Dbx1 data of Puelles et al (2016c) within the novel radial amygdalar model. They reached the conclusion, consistent with both radial glia pattern and Bielle et al.…”

“…7i-l; ). We hybridized in situ some sections of the horizontal series with the Lhx9 probe, which selectively labels the BMA and ACo nuclei of the anterior amygdalar radial unit, as well as the neighboring ventral subdivision of medial amygdala and the anterior amygdala Garcia-Calero and Puelles 2021). We also examined the distribution of the subpallial marker Dlx5, whose signal is absent from the NLOT2 and its migration stream (Fig.…”

“…The Lhx2/Lhx9 expressing amygdalar pallial cells were earlier thought to derive from the cortical ventral pallium (Medina et al 2004;Tole et al 2005;Puelles et al 2016b). However, and Garcia-Calero and Puelles (2021) reconsidered this notion, visualizing the Lhx9/Lhx2 combination as restricted primarily to the embryonic anterior radial amygdalar unit. They also described the secondary tangential migration of superficial BMA/ACo Lhx9/Lhx2 cells into the AA.…”

Genoarchitectonic Compartmentalization of the Embryonic Telencephalon: Insights From the Domestic Cat

“…Given that Emx1 is expressed in the anlagen of the BL and the PLCo ( Puelles et al, 2000 ; Medina et al, 2004 ), whereas Pax6 within the BM ( Puelles et al, 2000 ) and the Me ( Bupesh et al, 2011 ; Duan et al, 2013 ), we identified the dorsal Pax6 / Tbr2 expressing focus as the BM anlage. Moreover, we considered the superficial Tbr2 -expressing domain to represent superficial corticoid nuclei (ACo), given (1) its position between the Emx1 positive BL/PLCo and the Emx1 / Tbr1 negative Me primordia and (2) the fact that both BMA and ACo are products of the anterior amygdalar radial unit ( Garcia-Calero and Puelles, 2021 ). On the other hand, it could belong to the MePV, given that its core has been reported to express both Pax6 and Tbr2 ( Ruiz-Reig et al, 2018 ).…”

Sex-specific transcriptomic and epitranscriptomic signatures of PTSD-like fear acquisition

“…Functional expression of this gene in the adult hypothalamus has been recently linked to regulation of metabolism 21 . Lhx9 and Isl1 are transcription factors which also have roles in neurodevelopment 22, 23 . Fibcd1 belongs to a class of proteins known as fibrinogen-related domains (FreD) with multiple functions which include innate immunity and are expressed in glial cells in the human brain 24 .…”