刺激下肢穴位对吞咽中枢-岛叶皮质的激活效应：功能性磁共振成像的研究

The swallowing center-insula cortex activation evoked by stimulating acupoints of lower extremity ： a study using functional magnetic resonance imaging

目的研究刺激不同下肢穴位对岛叶皮质的激活效应。方法纳入健康右利手受试者20例接受功能性磁共振成像（fMRI）。采用3T磁共振成像系统采集全脑功能像。扫描时受试者放松闭眼，但不能入睡。穴位刺激采用组块方式。采用一块海绵以2Hz频率分别刷拂右下肢不同穴位。以SPM5软件包分析数据，采用混合效应模型进行组分析，以小范围容积校正（半径6mm）后P〈0．01作为阈值，检测岛叶皮质激活。结果刺激右下肢不同穴位均可在肢体对侧岛叶发现激活簇。不同穴位激活簇的位置、形态均有差别，但都分布于岛叶皮质后部。结论刺激下肢穴位能够激活岛叶后部皮质，这一效应可能通过易化吞咽动作启动、改善口咽部躯体感觉和味觉等多种途径促进吞咽功能的恢复。

Objective To investigate insula cortex activation evoked by stimulating different acupoints of lower extremity. Methods Twenty healthy male right-handed subjects were recruited to receive functional magnetic resonance imaging （fMRI） examination with a whole-body 3T Siemens Trio system for whole-brain imaging. Partici- pants were at rest during scanning and were instructed to relax with their eyes closed, without falling asleep. A blockdesigned method was applied for acupoint stimulation. The examined acupoints on the right lower extremity were stim- ulated, respectively, resulting in 4 experimental conditions. Stimulation was performed by brushing the subject＇s skin over each acupoint with a sponge at a frequency of approximately 2 Hz. Images were analyzed using SPM5 software package. Group analysis was performed with the mixed-effects model. Small volume correction was used to investigate insula cortex activation under each condition at a threshold of P 〈 0.01, with a 6-mm radius centered on the local maxima of activation in insula cortex. The scope of insula cortex was determined with SPM anatomy toolbox. Results All the examined acupoints induced activation in contralateral insula cortex. Activation clusters evoked by different acupoints presented various types of locations and shapes, and all of them located in the posterior part of insula cortex. Activation in the ipsilateral insula cortex was not found for all examined acupoints. Conclusions Stimulating lower extremity acupoints can activate posterior insula cortex. This effect may promote the recovery of dysphagia via several mechanisms including facilitating the initiation of swallowing, improving oral and pharyngeal sensation, and reducing taste disturbance.