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Chicken lateral septal organ and other circumventricular organs form in a striatal subdomain abutting the molecular striatopallidal border
Author(s) -
Bardet S.M.,
Cobos I.,
Puelles E.,
MartínezDeLaTorre M.,
Puelles L.
Publication year - 2006
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.21121
Subject(s) - circumventricular organs , biology , subfornical organ , neuroscience , anatomy , ganglionic eminence , striatum , forebrain , dlx5 , in situ hybridization , floor plate , homeobox , central nervous system , gene expression , gene , angiotensin ii , receptor , genetics , cerebrum , dopamine
The avian lateral septal organ (LSO) is a telencephalic circumventricular specialization with liquor‐contacting neurons (Kuenzel and van Tienhoven [1982] J. Comp. Neurol. 206:293–313). We studied the topological position of the chicken LSO relative to molecular borders defined previously within the telencephalic subpallium (Puelles et al. [2000] J. Comp. Neurol. 424:409–438). Differential expression of Dlx5 and Nkx2.1 homeobox genes, or the Shh gene encoding a secreted morphogen, allows distinction of striatal, pallidal, and preoptic subpallial sectors. The chicken LSO complex was characterized chemoarchitectonically from embryonic to posthatching stages, by using immunohistochemistry for calbindin, tyrosine hydroxylase, NKX2.1, and BEN proteins and in situ hybridization for Nkx2.1 , Nkx2.2 , Nkx6.1 , Shh , and Dlx5 mRNA. Medial and lateral parts of LSO appear, respectively, at the striatal part of the septum and adjacent bottom of the lateral ventricle (accumbens), in lateral continuity with another circumventricular organ that forms along a thin subregion of the entire striatum, abutting the molecular striatopallidal boundary; we called this the “striatopallidal organ” (SPO). The SPO displays associated distal periventricular cells, which are lacking in the LSO. Moreover, the SPO is continuous caudomedially with a thin, linear ependymal specialization found around the extended amygdala and preoptic areas. This differs from SPO and LSO in some molecular aspects. We tentatively identified this structure as being composed of an “extended amygdala organ” (EAO) and a “preoptohypothalamic organ” (PHO). The position of LSO, SPO, EAO, and PHO within a linear Dlx5 ‐expressing ventricular domain that surrounds the Nkx2.1 ‐expressing pallidopreoptic domain provides an unexpected insight into possible common and differential causal mechanisms underlying their formation. J. Comp. Neurol. 499:745–767, 2006. © 2006 Wiley‐Liss, Inc.