背景:岛叶皮层(IC)在处理内部感觉和情感信息中起着关键作用,提供对行为和认知方面性别差异的见解。IC包括两个不同的子区域:前岛叶皮层(aIC),处理情感和社会信号,和后岛叶皮层(pIC),专门研究疼痛的感觉和感知。IC内的金字塔形投影神经元整合了多模态感觉输入,影响行为和认知。尽管以前的研究集中在神经元连接和转录组学,在理解跨区域和性别的锥体神经元特征方面存在差距。
方法:处死成年雄性和雌性C57Bl/6J小鼠,收集含有IC的组织用于离体切片电生理学记录,其检查aIC和pIC亚区内突触可塑性和传递的基线性别差异。
结果:男性和女性的aIC和pIC神经元之间出现了明显的差异:aIC神经元表现出独特的特征,例如更大的大小,超极化增加,与它们的pIC对应物相比,具有更高的流变碱。此外,我们观察到与性别有关的神经元兴奋性的变化,男性pIC神经元比女性神经元表现出更高的兴奋性。我们还确定了雄性和雌性小鼠中兴奋性和抑制性突触活性的区域特异性差异以及兴奋和抑制之间的平衡。与pIC相比,成年雌性在aIC中表现出更大的突触强度和最大响应。最后,突触长时程增强发生在男性的两个亚区,但在女性的aIC特有。
结论:我们得出结论,IC亚区的突触可塑性和兴奋性传递存在性别差异,性别之间IC锥体神经元的不同特性可能导致男性和女性之间的行为和认知差异。
这项研究调查了岛叶皮层(IC)的差异,大脑中负责情绪和感官知觉的区域,在雄性和雌性小鼠之间。IC有两个部分:正面(aIC)处理情感和社交线索,而背部(pIC)则专注于感知疼痛和身体感觉。我们检查了aIC和pIC中称为锥体神经元的特定脑细胞,并发现了成年雄性和雌性小鼠中这些神经元之间的值得注意的区别。首先,aIC神经元更大,在雄性和雌性小鼠中具有独特的电特性。与女性相比,男性有更多的易激pIC神经元,表明它们的神经元更有可能传递信号。我们还探索了这些神经元如何通过称为突触的连接相互通信。在成年女性中,aIC比pIC有更强的连接。最后,我们观察到特定类型的基本突触学习仅发生在aIC中的男性中。这些发现强调了男性和女性在IC方面的显著差异,提供有价值的见解,以了解性别之间行为和情绪变化背后的潜在原因。
BACKGROUND: The insular cortex (IC) plays a pivotal role in processing interoceptive and emotional information, offering insights into sex differences in behavior and cognition. The IC comprises two distinct subregions: the anterior insular cortex (aIC), that processes emotional and social signals, and the posterior insular cortex (pIC), specialized in interoception and perception of pain. Pyramidal projection neurons within the IC integrate multimodal sensory inputs, influencing behavior and cognition. Despite previous research focusing on neuronal connectivity and transcriptomics, there has been a gap in understanding pyramidal neurons characteristics across subregions and between sexes.
METHODS: Adult male and female C57Bl/6J mice were sacrificed and tissue containing the IC was collected for ex vivo slice electrophysiology recordings that examined baseline sex differences in synaptic plasticity and transmission within aIC and pIC subregions.
RESULTS: Clear differences emerged between aIC and pIC neurons in both males and females: aIC neurons exhibited distinctive features such as larger size, increased hyperpolarization, and a higher rheobase compared to their pIC counterparts. Furthermore, we observed variations in neuronal excitability linked to sex, with male pIC neurons displaying a greater level of excitability than their female counterparts. We also identified region-specific differences in excitatory and inhibitory synaptic activity and the balance between excitation and inhibition in both male and female mice. Adult females demonstrated greater synaptic strength and maximum response in the aIC compared to the pIC. Lastly, synaptic long-term potentiation occurred in both subregions in males but was specific to the aIC in females.
CONCLUSIONS: We conclude that there are sex differences in synaptic plasticity and excitatory transmission in IC subregions, and that distinct properties of IC pyramidal neurons between sexes could contribute to differences in behavior and cognition between males and females.
This study investigates differences in the insular cortex (IC), a region of the brain responsible for emotions and sensory perceptions, between male and female mice. The IC has two parts: the front (aIC) deals with emotions and social cues, while the back (pIC) is focused on sensing pain and bodily sensations. We examined specific brain cells called pyramidal neurons in both aIC and pIC and discovered noteworthy distinctions between these neurons in adult male and female mice. Firstly, aIC neurons were larger and had unique electrical properties in both male and female mice. Males had more excitable pIC neurons compared to females, indicating that their neurons were more likely to transmit signals. We also explored how these neurons communicate with each other through connections known as synapses. In adult females, the aIC had stronger connections than the pIC. Finally, we observed that specific types of basic synaptic learning occurred exclusively in males in the aIC. These findings underscore significant disparities in the IC between males and females, offering valuable insights into the potential reasons behind variations in behaviors and emotions between sexes.