不同强度电刺激诱发岛叶激活的功能磁共振成像研究

目的利用功能磁共振成像技术(fMRI)观察不同强度电刺激作用下岛叶的激活反应,探讨岛叶在痛觉调控网络中的作用。方法采用GE公司1.5T超导型磁共振扫描系统,对10名右利手健康志愿者分别施加1倍痛阈、2倍痛阈、3倍痛阈三个不同强度的电刺激任务,同期进行脑功能活动的全脑fMRI扫描,应用功能性神经图像分析(AF-NI)软件包进行后处理以显示岛叶激活的变化。结果1倍痛阈强度电刺激诱发的脑激活区主要位于对侧岛叶后部;2倍痛阈强度电刺激诱发的脑激活区则集中于对侧岛叶前部,信号未见明显增强;当施加3倍痛阈强度电刺激时,双侧岛叶均表现出显著激活,且激活范围也有所增大。结论岛叶在痛觉调控网络中发挥了重要作用。在不同强度电刺激作用下,该区表现出分离性激活特性,其激活曲线呈现出较为特征性的“S”形曲线。

A functional MRI study on insula lobe activation induced by electrical stimulation of different intensity

Objective To observe regional changes of insula lobe action induced by electrical stimulation of different intensity in fMRI and discuss the effect of insula lobe in pain modulation network.Methods A total of 10 healthy right-handed volunteers were performed respectively with different electrical stimulus of 1,2,3 time pain threshold intensity.The whole-brain fMRI scannings were implemented at the same time.All data were postprocessed by means of AFNI to reveal the regional activated changes of insula lobe.Results The activation elicited by electrical stimulation with one time pain threshold intensity localized in contralateral posterior insula lobe,while two time pain threshold intensity mainly activated contralateral anterior insula lobe compared with that by one time's,and the BOLD signal showed no significant increase.When three time pain threshold intensity was applied,the bilateral insula lobe was observed with larger activated region remarkably.Conclusion Insula lobe may play an important role in pain modulation network.This activated brain area performs a spatial segregation and the stimulation intensity-response curve shows relatively characteristic "S-shaped".