PDF(Pubmed)
Abstract：
The amygdala is a complex brain structure in the vertebrate telencephalon, essential for regulating social behaviors, emotions, and (social) cognition. In contrast to the vast majority of neuron types described in the many nuclei of the mammalian amygdala, little is known about the neuronal diversity in non-mammals, making reconstruction of its evolution particularly difficult. Here, we characterize glutamatergic neuron types in the amygdala of the urodele amphibian Pleurodeles waltl. Our single-cell RNA sequencing data indicate the existence of at least ten distinct types and subtypes of glutamatergic neurons in the salamander amygdala. These neuron types are molecularly distinct from neurons in the ventral pallium (VP), suggesting that the pallial amygdala and the VP are two separate areas in the telencephalon. In situ hybridization for marker genes indicates that amygdalar glutamatergic neuron types are located in three major subdivisions: the lateral amygdala, the medial amygdala, and a newly defined area demarcated by high expression of the transcription factor Sim1. The gene expression profiles of these neuron types suggest similarities with specific neurons in the sauropsid and mammalian amygdala. In particular, we identify Sim1+ and Sim1+ Otp+ expressing neuron types, potentially homologous to the mammalian nucleus of the lateral olfactory tract (NLOT) and to hypothalamic-derived neurons of the medial amygdala, respectively. Taken together, our results reveal a surprising diversity of glutamatergic neuron types in the amygdala of salamanders, despite the anatomical simplicity of their brain. These results offer new insights on the cellular and anatomical complexity of the amygdala in tetrapod ancestors.
摘要：
杏仁核是脊椎动物端脑中复杂的脑结构，对于调节社会行为至关重要，情感和(社会)认知。与哺乳动物杏仁核的许多核中描述的绝大多数神经元类型相反，关于非哺乳动物的神经元多样性知之甚少，使其演变的重建特别困难。这里,我们表征了两栖动物侧耳的杏仁核中的谷氨酸能神经元类型。我们的单细胞RNA测序数据表明sal杏仁核中至少存在十种不同类型和亚型的谷氨酸能神经元。这些神经元类型在分子上不同于腹侧大脑皮层的神经元，这表明，在端脑中，杏仁核和腹侧大脑皮层是两个独立的区域。标记基因的原位杂交表明杏仁核谷氨酸能神经元类型位于三个主要分支中：杏仁核外侧，内侧杏仁核,以及一个新定义的区域，该区域由转录因子Sim1的高表达划定。这些神经元类型的基因表达谱表明与鼠尾草和哺乳动物杏仁核中的特定神经元相似。特别是,我们确定Sim1+和Sim1+Otp+表达神经元类型，可能与外侧嗅道（NLOT）的哺乳动物核和内侧杏仁核的下丘脑衍生神经元同源，分别。一起来看,我们的结果揭示了sal杏仁核中令人惊讶的谷氨酸能神经元类型的多样性，尽管他们的大脑解剖简单。这些结果为四足动物祖先杏仁核的细胞和解剖复杂性提供了新的见解。
