Rodent studies demonstrated specialized sodium chloride (NaCl) sensing neurons in the circumventricular organs, which mediate changes in sympathetic nerve activity, arginine vasopressin, thirst, and blood pressure. However, the neural pathways involved in NaCl sensing in the human brain are incompletely understood. The purpose of this pilot study was to determine if acute hypernatremia alters the functional connectivity of NaCl-sensing regions of the brain in healthy young adults. Resting-state fMRI scans were acquired in 13 participants at baseline and during a 30 min hypertonic saline infusion (HSI). We used a seed-based approach to analyze the data, focusing on the subfornical organ (SFO) and the organum vasculosum of the lamina terminalis (OVLT) as regions of interest (ROIs). Blood chemistry and perceived thirst were assessed pre- and post-infusion. As expected, serum sodium increased from pre- to post-infusion in the HSI group. The primary finding of this pilot study was that the functional connectivity between the SFO and a cluster within the OVLT increased from baseline to the late-phase of the HSI. Bidirectional connectivity changes were found with cortical regions, with some regions showing increased connectivity with sodium-sensing regions while others showed decreased connectivity. Furthermore, the functional connectivity between the SFO and the posterior cingulate cortex (a control ROI) did not change from baseline to the late-phase of the HSI. This finding indicates a distinct response within the NaCl sensing network in the human brain specifically related to acute hypernatremia that will need to be replicated in large-scale studies.

中文翻译：

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急性高钠血症增加人脑 NaCl 传感区域的功能连接：一项功能磁共振成像试点研究


啮齿动物研究表明，心室周围器官中有专门的氯化钠 (NaCl) 感应神经元，可介导交感神经活动、精氨酸加压素、口渴和血压的变化。然而，人类大脑中与氯化钠感应相关的神经通路尚不完全清楚。这项试点研究的目的是确定急性高钠血症是否会改变健康年轻人大脑中氯化钠感应区域的功能连接。 13 名参与者在基线和 30 分钟高渗盐水输注 (HSI) 期间获得了静息态 fMRI 扫描。我们使用基于种子的方法来分析数据，重点关注穹窿下器官 (SFO) 和终板血管器 (OVLT) 作为感兴趣区域 (ROI)。在输注前和输注后评估血液化学和感知口渴。正如预期的那样，HSI 组的血清钠从输注前到输注后有所增加。该试点研究的主要发现是，SFO 与 OVLT 内的集群之间的功能连接从 HSI 的基线到后期有所增加。皮质区域发现双向连接变化，一些区域与钠传感区域的连接增加，而另一些区域则显示连接减少。此外，SFO 和后扣带皮层（对照 ROI）之间的功能连接从基线到 HSI 的后期没有变化。这一发现表明，人脑中氯化钠传感网络内存在与急性高钠血症特别相关的独特反应，需要在大规模研究中进行复制。