Uhl Mara, Schmeisser Michael J, Schumann Sven
Institute for Microscopic Anatomy and Neurobiology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany.
Focus Program Translational Neurosciences, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany.
Front Mol Neurosci. 2022 Feb 18;15:818390. doi: 10.3389/fnmol.2022.818390. eCollection 2022.
A synaptic sexual dimorphism is relevant in the context of multiple neurodevelopmental, neurodegenerative, and neuropsychiatric disorders. Many of these disorders show a different prevalence and progression in woman and man. A similar variance is also present in corresponding animal models. To understand and characterize this dimorphism in pathologies it is important to first understand sex differences in unaffected individuals. Therefore, sexual differences have been studied since 1788, first focusing on brain weight, size, and volume. But as these measures are not directly related to brain function, the investigation of sexual dimorphism also expanded to other organizational levels of the brain. This review is focused on sexual dimorphism at the synaptic level, as these specialized structures are the smallest functional units of the brain, determining cell communication, connectivity, and plasticity. Multiple differences between males and females can be found on the levels of spine density, synaptic morphology, and molecular synapse composition. These differences support the importance of sex-disaggregated data. The specificity of changes to a particular brain region or circuit might support the idea of a mosaic brain, in which each tile individually lies on a continuum from masculinization to feminization. Moreover, synapses can be seen as the smallest tiles of the mosaic determining the classification of larger areas.
突触性二态性在多种神经发育、神经退行性和神经精神疾病的背景下具有相关性。这些疾病中的许多在女性和男性中表现出不同的患病率和进展情况。在相应的动物模型中也存在类似的差异。为了理解和表征病理状态下的这种二态性，首先了解未受影响个体的性别差异很重要。因此，自1788年以来就开始研究性别差异，最初侧重于脑重量、大小和体积。但由于这些测量与脑功能没有直接关系，对性二态性的研究也扩展到了大脑的其他组织层面。本综述聚焦于突触水平的性二态性，因为这些特殊结构是大脑最小的功能单位，决定着细胞通讯、连接性和可塑性。在脊柱密度、突触形态和分子突触组成水平上可以发现男性和女性之间的多种差异。这些差异支持了按性别分类的数据的重要性。特定脑区或回路变化的特异性可能支持镶嵌脑的概念，其中每个小块分别处于从男性化到女性化的连续体上。此外，突触可被视为镶嵌图中最小的小块，决定着更大区域的分类。
