Fang Chao, Wang Hong, Naumann Robert Konrad
CAS Key Laboratory of Brain Connectome and Manipulation, The Brain Cognition and Brain Disease Institute (BCBDI), Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, China.
Front Neuroanat. 2021 Dec 2;15:786329. doi: 10.3389/fnana.2021.786329. eCollection 2021.
The claustrum is an enigmatic brain structure thought to be important for conscious sensations. Recent studies have focused on gene expression patterns, connectivity, and function of the claustrum, but relatively little is known about its development. Interestingly, claustrum-enriched genes, including the previously identified marker , are not only expressed in the classical claustrum complex, but also embedded within lateral neocortical regions in rodents. Recent studies suggest that positive neurons in the lateral cortex share a highly conserved genetic expression pattern with claustrum neurons. Thus, we focus on the developmental progression and birth dating pattern of the claustrum and positive neurons in the lateral cortex. We comprehensively investigate the expression of at various stages of development in the rat and find that expression first appears as an elongated line along the anterior-posterior axis on embryonic day 13.5 (E13.5) and then gradually differentiates into multiple sub-regions during prenatal development. Previous birth dating studies of the claustrum have led to conflicting results, therefore, we combine 5-ethynyl-2'-deoxyuridine (EdU) labeling with hybridization for to study birth dating patterns. We find that most dorsal endopiriform (DEn) neurons are born on E13.5 to E14.5. Ventral claustrum (vCL) and dorsal claustrum (dCL) are mainly born on E14.5 to E15.5. positive cortical deep layer neurons (dLn) and superficial layer neurons (sLn) are mainly born on E14.5 to E15.5 and E15.5 to E17.5, respectively. Finally, we identify ventral to dorsal and posterior to anterior neurogenetic gradients within vCL and DEn. Thus, our findings suggest that claustrum and positive neurons in the lateral cortex are born sequentially over several days of embryonic development and contribute toward charting the complex developmental pattern of the claustrum in rodents.
屏状核是一种神秘的脑结构，被认为对意识感觉很重要。最近的研究集中在屏状核的基因表达模式、连接性和功能上，但对其发育的了解相对较少。有趣的是，富含屏状核的基因，包括先前确定的标记物，不仅在经典的屏状核复合体中表达，也存在于啮齿动物的外侧新皮质区域。最近的研究表明，外侧皮质中的阳性神经元与屏状核神经元具有高度保守的基因表达模式。因此，我们关注屏状核以及外侧皮质中阳性神经元的发育进程和出生时间模式。我们全面研究了大鼠发育各阶段的表达情况，发现其表达在胚胎第13.5天（E13.5）时首先沿前后轴呈一条长线出现，然后在产前发育过程中逐渐分化为多个亚区域。先前关于屏状核出生时间的研究结果相互矛盾，因此，我们将5-乙炔基-2'-脱氧尿苷（EdU）标记与杂交相结合来研究出生时间模式。我们发现，大多数背侧内梨状核（DEn）神经元在E13.5至E14.5出生。腹侧屏状核（vCL）和背侧屏状核（dCL）主要在E14.5至E15.5出生。外侧皮质深层阳性神经元（dLn）和浅层阳性神经元（sLn）分别主要在E14.5至E15.5和E15.5至E17.5出生。最后，我们确定了vCL和DEn内从腹侧到背侧以及从后到前的神经发生梯度。因此，我们的研究结果表明，屏状核和外侧皮质中的阳性神经元在胚胎发育的几天内依次出生，有助于描绘啮齿动物屏状核复杂的发育模式。
