Lee Dongha, Kim Do Yeob, To Xuan Vinh, Nasrallah Fatima A, Lee Hyung-Kun
Cognitive Science Research Group, Korea Brain Research Institute, 61 Cheomdan-ro, Dong-gu, Daegu, 41062, Republic of Korea.
Artficial Intelligence Creative Research Laboratory, Electronics and Telecommunications Research Institute (ETRI), 218 Gajeong-ro, Yuseong-gu, Daejeon, 34129, Republic of Korea.
Sci Rep. 2025 Sep 26;15(1):33264. doi: 10.1038/s41598-025-18556-z.
Anesthesia is essential, but not selective, in resting-state functional magnetic resonance imaging (fMRI) for pre-clinical studies. To mitigate stress and minimize head-movement artifacts, animals should be anesthetized during resting-state fMRI. Although the type, dosage, and timing of anesthesia can influence fMRI outcomes, responses to stimulation, and functional connectivity, the appropriate dosage of anesthesia is among the most important considerations. However, little is known about the effects of anesthetic dosage on innate fear responses induced by electrical stimulation. Therefore, we aimed to investigate the effects of medetomidine dosage on electrical stimulation and functional connectivity in fear-related regions. We conducted a graph-based network analysis of functional connectivity before and after electrical stimulation, based on different medetomidine dosages. We observed increased functional connectivity post-stimulation in the high-dose condition, but not in the low-dose condition. The high-dose condition showed increased global network properties post-stimulation compared to those observed pre-stimulation. In contrast, the low-dose condition showed no significant difference in global network properties between pre- and post-stimulation. The results suggest that high-dose medetomidine suppresses functional connectivity in fear-related regions in the brain; however, this suppressed functional connectivity can be recovered by electrical stimulation.
在临床前研究的静息态功能磁共振成像（fMRI）中，麻醉是必不可少的，但缺乏选择性。为了减轻应激并将头部运动伪影降至最低，在静息态fMRI期间应麻醉动物。尽管麻醉的类型、剂量和时机可影响fMRI结果、对刺激的反应以及功能连接性，但麻醉的适当剂量是最重要的考虑因素之一。然而，关于麻醉剂量对电刺激诱导的先天恐惧反应的影响知之甚少。因此，我们旨在研究美托咪定剂量对恐惧相关区域电刺激和功能连接性的影响。我们基于不同的美托咪定剂量，对电刺激前后的功能连接性进行了基于图的网络分析。我们观察到，高剂量条件下刺激后功能连接性增加，而低剂量条件下未增加。与刺激前相比，高剂量条件下刺激后全局网络属性增加。相比之下，低剂量条件下刺激前后全局网络属性无显著差异。结果表明，高剂量美托咪定抑制大脑中恐惧相关区域的功能连接性；然而，这种受抑制的功能连接性可通过电刺激恢复。
