Vicario Alba, Abellán Antonio, Desfilis Ester, Medina Loreta
Department of Experimental Medicine, Laboratory of Brain Development and Evolution, Institute of Biomedical Research of Lleida, University of Lleida Lleida, Spain.
Front Neuroanat. 2014 Sep 10;8:90. doi: 10.3389/fnana.2014.00090. eCollection 2014.
In mammals, the central extended amygdala shows a highly complex organization, and is essential for animal survival due to its implication in fear responses. However, many aspects of its evolution are still unknown, and this structure is especially poorly understood in birds. The aim of this study was to define the central extended amygdala in chicken, by means of a battery of region-specific transcription factors (Pax6, Islet1, Nkx2.1) and phenotypic markers that characterize these different subdivisions in mammals. Our results allowed the identification of at least six distinct subdivisions in the lateral part of the avian central extended amygdala: (1) capsular central subdivision; (2) a group of intercalated-like cell patches; (3) oval central nucleus; (4) peri-intrapeduncular (peri-INP) island field; (5) perioval zone; and (6) a rostral part of the subpallial extended amygdala. In addition, we identified three subdivisions of the laterodorsal bed nucleus of the stria terminalis (BSTLd) belonging to the medial region of the chicken central extended amygdala complex. Based on their genetic profile, cellular composition and apparent embryonic origin of the cells, we discuss the similarity of these different subdivisions of chicken with different parts of the mouse central amygdala and surrounding cell masses, including the intercalated amygdalar masses and the sublenticular part of the central extended amygdala. Most of the subdivisions include various subpopulations of cells that apparently originate in the dorsal striatal, ventral striatal, pallidal, and preoptic embryonic domains, reaching their final location by either radial or tangential migrations. Similarly to mammals, the central amygdala and BSTLd of chicken project to the hypothalamus, and include different neurons expressing proenkephalin, corticotropin-releasing factor, somatostatin or tyrosine hydroxylase, which may be involved in the control of different aspects of fear/anxiety-related behavior.
在哺乳动物中，中央杏仁核扩展区呈现出高度复杂的组织结构，因其在恐惧反应中的作用而对动物生存至关重要。然而，其进化的许多方面仍不为人知，而且这种结构在鸟类中尤其难以理解。本研究的目的是通过一系列区域特异性转录因子（Pax6、Islet1、Nkx2.1）和表型标记来定义鸡的中央杏仁核扩展区，这些转录因子和标记可表征哺乳动物中这些不同的亚区。我们的研究结果确定了鸟类中央杏仁核扩展区外侧部分至少六个不同的亚区：（1）被囊中央亚区；（2）一组类似闰细胞的细胞团块；（3）椭圆形中央核；（4）脚间周（peri-INP）岛状区；（5）椭圆周区；（6）皮质下杏仁核扩展区的前部。此外，我们确定了终纹床核外侧背核（BSTLd）的三个亚区，它们属于鸡中央杏仁核扩展复合体的内侧区域。基于它们的基因特征、细胞组成以及细胞明显的胚胎起源，我们讨论了鸡的这些不同亚区与小鼠中央杏仁核不同部分及周围细胞团块（包括杏仁核闰细胞团块和中央杏仁核扩展区的豆状核下部分）的相似性。大多数亚区包括各种明显起源于背侧纹状体、腹侧纹状体、苍白球和视前胚胎区域的细胞亚群，通过径向或切向迁移到达其最终位置。与哺乳动物类似，鸡的中央杏仁核和BSTLd投射到下丘脑，并且包括表达前脑啡肽、促肾上腺皮质激素释放因子、生长抑素或酪氨酸羟化酶的不同神经元，这些神经元可能参与恐惧/焦虑相关行为不同方面的控制。
